realproducer user`s guide

Transcription

REALPRODUCER USER’S GUIDE
RealProducer 13.1
Revision Date: 18 December 2009
RealNetworks, Inc.
P.O. Box 91123
Seattle, WA 98111-9223
U.S.A.
http://www.real.com
http://www.realnetworks.com
Copyright ©2004-2009 RealNetworks, Inc. All rights reserved.
Information in this document is subject to change without notice. All rights reserved. No part of this book may
be reproduced, in any form or by any means, without permission in writing from RealNetworks, Inc.
Helix, the Helix logo, the Real "bubble" (logo), RealProducer, Helix Producer, RealSystem Server, Helix Universal
Server, RealAudio, RealVideo, RealMedia, RealPlayer, and RealOne Player are all trademarks or registered
trademarks of RealNetworks, Inc.
Other product and corporate names may be trademarks or registered trademarks of their respective owners.
-------------------------------
Copyright (c) 1995-2009 RealNetworks, Inc. This product may incorporate one or more of the following: U.S.
Patent # 5,917,835; U.S. Patent # 5,854,858; U.S. Patent # 5,917,954; U.S. Patent # 6,597,961; U.S. Patent
#6,314,466. Other U.S. patents pending. All rights reserved.
RealNetworks Lossless audio codec Copyright (c) 1999-2003 RealNetworks, Inc. All rights reserved.
RealNetworks RealAudio Multichannel Codec Copyright (c) 2003 RealNetworks, Inc. All rights reserved.
ACELP(r).net codec by VoiceAge Corporation Copyright(c) 2000-2002. All rights reserved.
AAC and aacPlus implementation developed by Coding Technologies. All rights reserved.
The Ogg Multimedia Framework and the Vorbis audio compression tools have been provided by the Xiph.org
Foundation.
RealNetworks RealVideo 8 video codec Copyright (c) 1995-2004 RealNetworks, Inc. Portions Copyright (c)
1999-2000 Intel Corporation. All rights reserved.
STLport (c) 1999, 2000 Boris Fomitchev. Copyright (c) 1994 Hewlett-Packard Company. Copyright (c) 1996,97
Silicon Graphics Computer Systems, Inc. Copyright (c) 1997 Moscow Center for SPARC Technology.
Helix, RealAudio, RealNetworks, RealSystem, RealVideo, and SureStream are trademarks or registered
trademarks of RealNetworks, Inc. All other companies or products listed herein are trademarks or registered
trademarks of their respective owners. All rights reserved.
CONTENTS
INTRODUCTION
1
How This Guide Is Organized ............................................................................ 1
Conventions Used in this Guide......................................................................... 3
PART I: GETTING STARTED
1
INSTALLATION
7
System Requirements........................................................................................ 7
Installing on Windows ...................................................................................... 7
Windows .Net RunTime................................................................................ 8
Uninstalling the Program .............................................................................. 8
2
CODECS AND FILE FORMATS
11
Input Formats .................................................................................................11
Uncompressed Input Formats ......................................................................11
Formats Requiring DirectX ...........................................................................11
Formats Requiring QuickTime......................................................................12
Output Choices...............................................................................................12
RealMedia ..................................................................................................12
Audio Codec Choices ......................................................................................13
RealAudio...................................................................................................13
Video Codec Choices .......................................................................................17
RealVideo ...................................................................................................17
Multi-Rate Streams..........................................................................................18
Rate Shifting ...............................................................................................19
Encoding Requirements for Rate-Shifting Clips .............................................19
PART I: INPUTS AND OUTPUTS
3
INPUTS
25
Input Tab........................................................................................................25
Jobs and Job Files ............................................................................................26
Loading an Existing Job................................................................................27
Upgrading Older Job Files ............................................................................27
File Input ........................................................................................................27
iii
RealProducer User’s Guide
Video Source File Size Limit..........................................................................28
Capture Input .................................................................................................29
Input Duration............................................................................................29
Audio Mixer ................................................................................................30
Audio Vendor Controls................................................................................30
Video Settings .............................................................................................31
Timeline Editor ...............................................................................................33
Timeline Editing Controls ............................................................................34
Source Properties ............................................................................................35
4
PREFILTERS
37
Audio and Video Preprocessing ........................................................................37
Controls for Displaying and Enabling Prefilters .............................................38
Audio Level .....................................................................................................38
Audio Synchronization ....................................................................................39
Input Cropping ...............................................................................................39
Cropping Controls ......................................................................................40
De-Interlace and Inverse-Telecine .....................................................................41
Inverse-Telecine Prefilter ..............................................................................42
De-Interlace Prefilter....................................................................................42
Video Noise ....................................................................................................43
Low Noise Filtering......................................................................................44
High Noise Filtering.....................................................................................44
Input Resize ....................................................................................................44
Resize Controls ...........................................................................................45
Maintain Aspect Ratio.................................................................................46
High-Quality Resize .....................................................................................46
Black-Level Correction .....................................................................................46
5
OUTPUTS
47
Output Tab ....................................................................................................47
Single Outputs and Multiple Outputs...........................................................48
Outputs and Destinations ...........................................................................48
Outputs List....................................................................................................49
Output Selection.........................................................................................50
Output Name .............................................................................................50
Encoding Settings............................................................................................50
Audience Control Buttons ...........................................................................51
Audience Templates ....................................................................................51
Audience Customization..............................................................................52
Output File Destination ...................................................................................55
Archive Clips ...............................................................................................55
Output File Extension ..................................................................................55
iv
Contents
Two-Pass Encoding .....................................................................................56
Output File Size...........................................................................................56
Metadata........................................................................................................57
Metadata Buttons .......................................................................................57
Metadata Entry ...........................................................................................58
Metadata Titles and Values ..........................................................................58
PART II: ADVANCED AUDIO AND VIDEO SETTINGS
6
AUDIO CUSTOMIZATION
63
Audio Encoding Settings ..................................................................................63
Audio Codec ..................................................................................................64
Channels.........................................................................................................64
What is Stereo Surround? ............................................................................65
What is Multichannel Audio? .......................................................................66
Average Bit Rate ..............................................................................................67
Sample Rate....................................................................................................68
What is a Sampling Rate? ............................................................................68
7
VIDEO CUSTOMIZATION
69
Video Encoding Settings ..................................................................................69
Video Codec....................................................................................................70
Level ...............................................................................................................70
Video Average Bit Rate.....................................................................................70
Frame Rate .....................................................................................................71
Target Frame Rates......................................................................................71
Factors that Affect RealVideo Frame Rates....................................................71
Frame Size.......................................................................................................72
Maintain Aspect Ratio .................................................................................73
High-Quality Resize .....................................................................................73
Notes on Resizing ........................................................................................73
Encoding Complexity .......................................................................................75
Frame Rate Mode............................................................................................76
8
ADVANCED VIDEO OPTIONS
77
Advanced Video Settings ..................................................................................77
Variable Bit Rate Video ....................................................................................78
VBR Compared to CBR................................................................................78
VBR Maximum Bit Rate ...............................................................................79
VBR Target Quality......................................................................................80
Maximum Video Buffering (Preroll) ..................................................................81
Maximum Key Frame Interval ...........................................................................82
What is a Key Frame? ..................................................................................82
v
Advantages of Lowering the Maximum Key Frame Interval .............................82
Costs of Lowering the Maximum Key Frame Time..........................................83
Startup Latency Reduction During Broadcasts ..............................................83
PART III: BROADCASTING
9
BROADCAST FEATURES
87
Live Broadcasting ............................................................................................87
Broadcast Trial Runs ...................................................................................88
Types of Broadcasts ........................................................................................88
Helix Push Broadcast...................................................................................89
Helix Advanced Push Broadcast ...................................................................91
Helix Multicast Push Broadcast....................................................................92
Helix Pull Broadcast ....................................................................................94
Server Broadcast Mode....................................................................................96
Broadcast Transports ......................................................................................97
Encoder Redundancy.......................................................................................97
Forward Error Correction.................................................................................98
Error Correction Percentage.........................................................................99
Redundant Stream Protection......................................................................99
FEC Rates and Receiver Buffering .................................................................99
Archiving ......................................................................................................100
RealProducer Archiving..............................................................................100
Helix Server Archiving ................................................................................101
Version 6 IP Addresses ...................................................................................101
10
SERVER DESTINATIONS
103
Server Destinations........................................................................................103
Output Servers Buttons .............................................................................103
Server Destination Templates.....................................................................104
Helix Push Destination...................................................................................105
Helix Push Basic Settings ...........................................................................106
Helix Push Advanced Settings.....................................................................108
Helix Advanced Push Destination ...................................................................110
Helix Advanced Push Basic Settings ............................................................110
Helix Advanced Push Advanced Settings .....................................................113
Helix Multicast Push Destination....................................................................114
Helix Multicast Push Basic Settings ............................................................115
Helix Multicast Push Advanced Settings......................................................117
Helix Pull Destination ....................................................................................118
Helix Pull Basic Settings .............................................................................119
Helix Pull Advanced Settings ......................................................................122
vi
Contents
PART IV: MONITORING
11
JOB MONITORING
125
Monitoring Tab.............................................................................................125
Starting a Job ...............................................................................................126
Preview Section .............................................................................................126
Multiple Output Display ............................................................................127
Audio Meters ................................................................................................127
Clipped Audio...........................................................................................128
Session Logging.............................................................................................129
Session Log Viewer ....................................................................................129
Logging Types ...........................................................................................129
Settings Advisor.............................................................................................130
PART V: APPENDIXES
A
PREFERENCES
133
Preferences File..............................................................................................133
File Location Preferences................................................................................133
Template Directories .................................................................................134
Temporary Directory..................................................................................134
Log File Preferences .......................................................................................135
Log File Location .......................................................................................135
Logging Settings ........................................................................................135
Log File Rolling..........................................................................................137
Output Preferences........................................................................................138
Encoding Defaults .....................................................................................139
Output Directory and File Name Defaults ...................................................139
Output Server Defaults ..............................................................................140
Metadata Defaults ....................................................................................140
Signal Detection Preferences ..........................................................................140
Audio Watchdog Tests ..............................................................................141
Video Watchdog Tests ...............................................................................142
Message Suppression.................................................................................144
Frame Analysis Period................................................................................144
B
AUDIENCE TEMPLATES
145
Predefined Audience Templates......................................................................145
Templates Included with RealProducer .......................................................145
Customized Templates ..............................................................................146
16k Voice ......................................................................................................146
28k Video......................................................................................................147
32k Music .....................................................................................................148
vii
56k Video .....................................................................................................148
64k Music.....................................................................................................149
65k Video .....................................................................................................150
80k Video .....................................................................................................150
96k Music.....................................................................................................151
100k Video ...................................................................................................152
150k Video ...................................................................................................152
300k Video ...................................................................................................153
750k Video ...................................................................................................154
1.5M Video...................................................................................................155
90% VBR Quality Video..................................................................................155
C
AUDIO AND VIDEO TIPS
157
Audio Capture ..............................................................................................157
Source Media............................................................................................157
Recording Equipment................................................................................157
Shielded Cables.........................................................................................158
Input Levels...............................................................................................158
Volume Levels for Live Broadcasts ..............................................................158
Sampling Rates .........................................................................................158
Audio Optimization ......................................................................................159
DC Offset .................................................................................................159
Normalization...........................................................................................159
Dynamics Compression .............................................................................160
Equalization..............................................................................................160
Video Recording............................................................................................161
Video Staging............................................................................................161
Scene Changes and Movement...................................................................161
Colors and Lighting ...................................................................................161
Video Output............................................................................................162
Color Depth..............................................................................................162
Source Media Quality ................................................................................162
INDEX
viii
163
INTRODUCTION
This guide explains how to use the graphical application of
RealProducer 13.1 to encode on-demand clips and live broadcasts. It
describes the file formats and codecs that RealProducer can use to
create output. It also explains how to customize audio and video
output to meet your viewers’ needs.
For More Information: An additional guide, RealProducer
Command Line and Job File Reference, explains how to run
RealProducer 13.1 from the command line. It also describes
the syntax of the job, audience, and server files used by the
graphical application.
How This Guide Is Organized
The guide contains the following chapters.
Chapter 1: Installation
This chapter covers RealProducer requirements and installation.
Chapter 2: Codecs and File Formats
This chapter explains the output file formats and codecs that RealProducer
supports.
Chapter 3: Inputs
As explained in this chapter, you can encode audio and video from a file or live
input.
Chapter 4: Prefilters
By applying prefilters to the input, you can improve the audio and video
quality as well as crop and resize a video.
1
Chapter 5: Outputs
This chapter explains how to define outputs and select audiences to control
how the output is encoded.
Chapter 6: Audio Customization
In many instances, you’ll want to refine the audio settings by customizing an
audience definition.
Chapter 7: Video Customization
You can also customize the video settings of an audience to change, for
example, the video codec used to encode the output.
Chapter 8: Advanced Video Options
This chapter explains advanced video customizations, such as defining the
video preroll and creating a variable bit rate clip.
Chapter 9: Broadcast Features
Refer to this chapter for basic information about broadcasting a live stream.
Chapter 10: Server Destinations
When you are ready to broadcast a live event, you set up a server destination
using the instructions in this chapter.
Chapter 11: Job Monitoring
This chapter explains how to start, stop, and monitor an encoding job.
Appendix A: Preferences
This appendix explains how to modify the RealProducer preferences to set
overall encoding preferences.
Appendix B: Audience Templates
Audience templates define encoding settings such as the streaming bit rate.
This appendix describes the predefined templates included with
RealProducer.
Appendix C: Audio and Video Tips
Good quality starts at the source. This appendix provides tips for creating
high-quality audio and video input.
2
Introduction
Conventions Used in this Guide
The following table explains the typographical conventions used in this guide.
Notational Conventions
Convention
Meaning
emphasis
Bold text is used for in-line headings, user-interface
elements, URLs, and e-mail addresses.
terminology
Italic text is used for technical terms being introduced,
and to lend emphasis to generic English words or phrases.
syntax
This font is used for fragments or complete lines of
programming syntax (markup).
syntax emphasis Bold syntax character formatting is used for program
names, and to emphasize specific syntax elements.
variables
Italic syntax character formatting denotes variables
within fragments or complete lines of syntax.
[options]
Square brackets indicate values that you may or may not
need to use. As a rule, when you use these optional values,
you do not include the brackets themselves.
choice 1|choice 2 Vertical lines, or “pipes,” separate values that you can
choose between.
...
Ellipses indicate nonessential information omitted from
examples.
3
4
PART
Part I:
GETTING STARTED
This section explains how to install RealProducer 13.1. It also
covers the file formats and codecs that RealProducer can use
when encoding on-demand clips or live broadcasts.
I
CHAPTER
Chapter 1:
1
INSTALLATION
This chapter describes the hardware and software requirements for
RealProducer. It then explains how to install the product.
System Requirements
The following table lists the requirements for using RealProducer 13.1.
RealProducer 13.1 System Requirements
Hardware or Software
Requirement
Windows Version
Windows XP SP3
Windows Vista
Windows 7
Windows Server 2003
Windows Server 2008
Windows .Net runtime .Net 2.0 (automatically installed if not present)
Windows Installer
version 3.0 (included with Windows XP SP2 and later)
CPU (minimum)
Pentium 4 or Core2Duo (recommended)
RAM (minimum)
512 MB
Display Resolution
1024x768 pixels or greater
Note: When encoding multiple outputs, RealProducer uses
each processor core to encode an output. A four-core processor
can encode four outputs at the same time, for example.
Installing on Windows
To install RealProducer, you need a binary installation file that enables the
RealProducer features..
Note: Your account must have Administrator privileges to
install RealProducer.
7
For More Information: See “System Requirements” on page 7 for
computer hardware and software requirements.
➤
To install RealProducer onto Windows:
1. Close all running applications.
2. Double-click on the installation program icon. The installer unpacks the
required files and opens the installation dialog.
3. Choose the product to install.
4. Read the license and click Accept to agree to its terms.
5. The next page allows you to choose the installation location. The default
directory is under C:\Program Files\ . You can change this directory by
clicking the Browse button and selecting the new path.
Note: The installer adds the installation directory to your
Windows PATH variable. This allows you to run the commandline application from any directory on your machine. If you do
not want to update the PATH value, remove the checkmark
from the option.
Tip: You must log out of Windows and log back in before a
Path variable update takes effect.
6. In the final confirmation screen, verify your choices and click Install.
Windows .Net RunTime
On Windows, RealProducer installs Microsoft .Net 2.0 SP1 if it is not present
already. This installation does not affect other versions of the .Net runtime.
For example, you can have .Net 3.0 and 3.5 installed on the same machine
without conflict.
Note: If the installer included the .Net runtime, you will need
to reboot your machine after the installation completes.
Uninstalling the Program
To remove RealProducer from your machine, use the Add or Remove Programs
dialog of the Windows Control Panel. The removal process deletes all files that
8
CHAPTER 1: Installation
were created by the installer. However, it does not remove any encoded outputs
or job files created by RealProducer.
9
10
CHAPTER
Chapter 2:
CODECS AND FILE FORMATS
2
This chapter explains the input and output formats, audio codecs,
and video codecs that you can use with RealProducer.
Input Formats
When creating content to encode, use uncompressed formats whenever
possible. Otherwise, you compress the source once when you digitize it and
again when you encode it in a streaming format. This double compression can
decrease the image quality. Use a compressed source format only if
RealProducer supports the file as input.
Tip: Always keep copies of the video source files. You cannot
convert encoded clips back to their original source formats or
transcode them to other streaming formats.
Uncompressed Input Formats
You can use the following file formats as input sources on any operating
system that runs RealProducer. Using these formats does not require
installing other audio and video software:
• Uncompressed
• WAV
QuickTime 3, 4, and 5 (.mov )
audio files (.wav )
• Uncompressed
AVI (.avi )
Formats Requiring DirectX
You can use the following file formats as inputs on Windows if you have
DirectX 9.1 or higher installed:
• Compressed
AVI (.avi )
• AIFF (.aif, .aifc, .aiff )
11
• QuickTime
2 (.mov )
• MPEG
Note: Using MPEG-2 requires the DirectShow MPEG-2 reader.
Tip: If you experience problems using MPEG inputs under
DirectX, install QuickTime.
For More Information: For the latest version of DirectX, go to
http://www.microsoft.com.
Formats Requiring QuickTime
The following file formats can be used as sources on Windows if the latest
version of QuickTime is installed:
• AU (.au, .snd, .ulw )
• Sound
Designer II (.sd2 )
• DV (.dif, .dv )
• QuickTime
Flattened Movie (.mov, .qt )
• MPEG
For More Information: For more about QuickTime, visit
http://www.apple.com/quicktime/.
Output Choices
RealProducer constrains the available audio and video encoding options to
values appropriate for the output type.
For More Information: See “Outputs List” on page 49 for
information about how you choose the output type.
RealMedia
The RealMedia output is a proprietary RealNetworks format.
players: Desktop versions of RealPlayer. Mobile devices based on Helix
technology.
file type: RealMedia (.rm , .ra , .rv, .rmvb )
12
CHAPTER 2: Codecs and File Formats
audio: RealAudio
video: RealVideo
multi-rate: yes (see “Multi-Rate Streams” on page 18)
Audio Codec Choices
The following are the audio codecs that you can choose. Note that all audio
codecs encode at discrete bandwidths only. For example, RealAudio stereo
music codecs provide 44 Kbps and 64 Kbps choices, but no bandwidths inbetween.
For More Information: See “Audio Encoding Settings” on page
63 for details about how you choose an audio codec and select
the audio bit rate.
RealAudio
You can use RealAudio as a stand-alone audio format, or as the audio track of
a RealVideo clip.
audio type: voice, music
channels: mono, stereo, stereo-surround, multichannel
file types: RealMedia (.rm , .ra , .rmvb )
video: RealVideo
The following sections describe the RealAudio codecs available through
RealProducer. The codecs are listed in separate tables for voice, mono music,
stereo music, stereo surround, and multichannel audio.
RealAudio Voice Codecs
Voice codecs produce the best results for voice-only audio input.
RealAudio Voice Codecs
Bandwidth
Codec
Channels
Sampling Rate
5 Kbps
RealAudio Voice
1
8000
6.5 Kbps
RealAudio Voice
1
8000
8.5 Kbps
RealAudio Voice
1
8000
13
RealAudio Voice Codecs (continued)
Bandwidth
Codec
Channels
Sampling Rate
16 Kbps
RealAudio Voice
1
16000
32 Kbps
RealAudio Voice
1
22050
64 Kbps
RealAudio Voice
1
44100
Tip: The lowest-speed voice codec normally used to encode a
RealAudio clip is 16 Kbps. The lower-speed codecs (5, 6.5, and
8.5 Kbps) are used as duress streams when the connection
bandwidth drops in a multi-rate clip. They’re also used to
encode soundtracks for low-bandwidth RealVideo clips.
RealAudio High-Response Codecs
A high-response codec may have up to twice the range as a normal-response
codec. This means it provides crisper sound and captures higher frequencies.
High-response codecs are available for mono and stereo encoding.
RealAudio High-Response Music Codecs
Bandwidth
Codec
Channels Sampling Rate
20 Kbps
RealAudio High Response 1
22050
20 Kbps
22050
32 Kbps
44100
32 Kbps
44100
44 Kbps
44100
Tip: A high-response codec may produce more distortion with
voices and loud sounds such as drums. If you are encoding
music with a diverse range of frequencies, use a high-response
codec first. If you notice distortion, compare your results with
a clip that uses a normal-response codec.
14
RealAudio Mono Music Codecs
Use mono music codecs for encoding mono input or stereo input for mono
output.
RealAudio Mono Music Codecs
Bandwidth
Codec
Channels
Sampling Rate
6 Kbps
RealAudio
1
8000
8 Kbps
RealAudio
1
8000
11 Kbps
RealAudio
1
8000
16 Kbps
RealAudio
1
8000
20 Kbps
RealAudio
1
11025
32 Kbps
RealAudio
1
22050
44 Kbps
RealAudio
1
44100
64 Kbps
RealAudio
1
44100
RealAudio Stereo Music Codecs
Use stereo music codecs for encoding traditional, two-channel stereo music.
RealAudio Stereo Music Codecs
Bandwidth
Codec
Channels
Sampling Rate
12 Kbps
RealAudio
2
11025
16 Kbps
RealAudio
2
22050
20 Kbps
RealAudio
2
22050
32 Kbps
RealAudio
2
22050
44 Kbps
RealAudio
2
44100
64 Kbps
RealAudio
2
44100
96 Kbps
RealAudio
2
44100
128 Kbps
RealAudio
2
44100
160 Kbps
RealAudio
2
44100
192 Kbps
RealAudio
2
44100
256 Kbps
RealAudio
2
44100
320 Kbps
RealAudio
2
44100
15
RealAudio Stereo-Surround Codecs
Encode your audio using a stereo-surround codec if you know that the source
audio is matrixed, multiple-channel sound, and you wish to preserve the
multiple channels for your listeners.
RealAudio Stereo-Surround Codecs
Bandwidth
Codec
Channels
Sampling Rate
44 Kbps
RealAudio
2s
22050
64 Kbps
RealAudio
2s
44100
96 Kbps
RealAudio
2s
44100
128 Kbps
RealAudio
2s
44100
160 Kbps
RealAudio
2s
44100
192 Kbps
RealAudio
2s
44100
256 Kbps
RealAudio
2s
44100
RealAudio
2s
44100
320 Kbps
For More Information: See “What is Stereo Surround?” on page
65.
RealAudio 5.1 Multichannel Audio Codecs
Use the multichannel RealAudio codecs if you know that the source audio
includes multichannel sound, and your intended listeners have systems able to
play all of the channels.
RealAudio Multichannel Codecs
Bandwidth
Codec
Channels
Sampling Rate
96 Kbps
RealAudio
5.1
44100
132 Kbps
RealAudio
5.1
44100
184 Kbps
RealAudio
5.1
22050
268 Kbps
RealAudio
5.1
22050
For More Information: See “What is Multichannel Audio?” on
page 66.
16
Video Codec Choices
The following are the video codecs that you can choose. Note that video
codecs encode at any bandwidth. For example, if your target bandwidth is 100
Kbps and you choose a 32 Kbps audio codec, the video track automatically
encodes at 68 Kbps.
For More Information: See “Video Encoding Settings” on page
69 for details about how to select a video codec.
RealVideo
RealProducer encodes RealVideo clips using a RealAudio soundtrack.
rate control: constant bit rate (CBR), variable bit rate (VBR)
versions: 8, 9, 10
file types: RealMedia (.rm , .rv, .rmvb )
audio: RealAudio
RealVideo 10 Codec
The RealVideo 10 codec creates the highest quality RealVideo content. It offers
improved visual quality over RealVideo 9 and RealVideo 8, especially with fastaction scenes and on-screen text. This is the default RealVideo codec used by
RealProducer.
Note: Because RealVideo 10 performs more complex analysis of
video data than earlier codecs, encoding may take more than
twice the time required with RealVideo 9. Use a different
RealVideo codec if you need faster encoding performance
during broadcasts.
RealVideo 9 Codec
RealVideo 9 improves on RealVideo 8 with higher compression and improved
visual quality. RealOne Player and later can play RealVideo 9 clips. Users who
have older versions of RealPlayer are prompted to autoupdate when
attempting to play a RealVideo 9 clip.
17
RealVideo 8 Codec
The RealVideo 8 codec is compatible with RealPlayer 8 and later. The video
quality is not as high as with RealVideo 9 and 10, but encoding is faster.
Additionally, RealVideo 8 requires fewer resources on the RealPlayer machine
to decompress. This makes it suitable for the slower processors of mobile
devices.
Multi-Rate Streams
With RealMedia output, you can encode an audio-only stream or a video
stream for multiple bandwidths. For example, you can create a single
RealVideo clip that streams at 56, 128, or 256 Kbps by choosing audiences
that encode the same input at different bandwidths. When a viewer requests
the clip, Helix Server determines which stream to use based on the available
bandwidth, as shown in the following illustration.
Clip Encoded for Multiple Bandwidths
Note: Each stream that you add to a multi-rate clip increases
the clip’s file size. Streams for higher bandwidths increase the
file size more than streams for lower bandwidth because highbandwidth encodings include more data.
Tip: Including multiple audiences in an output increases the
processing time needed to encode the stream. This can become
a critical issue during live broadcasts because RealProducer
must encode all outputs in real-time. When running a
18
broadcast, carefully choose the audiences included in the
output.
For More Information: The section “Audience Templates” on
page 51 explains how to add multiple audiences to an output.
See “Live Broadcasting” on page 87 for background about
running a live broadcast.
Rate Shifting
A rate-shifting clip is a type of multi-rate clip that allows Helix Server to switch
between different audience encodings to compensate for network conditions.
The following figure illustrates a media session becoming bogged down
because of excessive network traffic. Helix Server downshifts to a lowerbandwidth stream to prevent the presentation from stalling. When the
congestion clears, Helix Server upshifts to a higher-bandwidth stream.
Rate Control During Network Congestion
Encoding Requirements for Rate-Shifting Clips
The following conditions must exist to enable Helix Server and the media
client to shift between audiences during a streaming session:
• The
Helix Server rate control feature must be enabled and configured.
For More Information: See Helix Server Administration Guide for
information about this feature.
19
• The
audiences encoded in the clip must be compatible. The following
sections explain the requirements for enabling rate shifting when using
multiple audiences.
Audience Streaming Rates
When you create a rate-shifting clip, chose the audience streaming rates
carefully. If rates are too close together, the media player may shift rates
continuously, which creates a poor user experience. If rates are too far apart,
the media player may not be able to shift rates at points where doing so would
be advantageous.
You may need to experiment with settings until you find audiences that work
well for your viewers and your network. To start, follow these principles:
• Set
the top streaming rate to approximately 80 percent of the ideal
throughput. To target a 256 Kbps network speed, for example, set the topspeed audience to stream at 200 Kbps.
• Create a
compatible audience that streams at approximately 80 percent of
the top-speed audience: 160 Kbps, for example. The media player can shift
to this audience if the network throughput slows.
Helix Server Oversend Rate
When you encode a multi-rate clip or broadcast for rate control, Helix Server
allows upshifting to the next higher stream rate only if that rate is no more
than a certain percentage above the current rate. This is called the maximum
oversend rate.
Suppose that the maximum oversend rate is 300 percent. For a clip encoded
with 56, 128, and 256 Kbps streams, the media player can upshift through all
of the streams because no rate is more than 300 percent of the preceding rate.
If the clip contains just 56 and 256 Kbps streams, however, the media player
cannot upshift from the 56 Kbps stream.
For More Information: The maximum oversend rate is
configurable for each Helix Server. For details, refer to the rate
control chapters in Helix Server Administration Guide and Helix
Server Configuration and Registry Reference.
Audio and Video Codecs
In a rate-shifting clip, you must encode all video audiences using the same
RealVideo codec. For example, you cannot encode one audience with
20
RealVideo 8 while encoding another audience with RealVideo 10. Audiences
for rate-shifting clips can use different versions of the RealAudio codec,
however.
For More Information: See “Audio Codec” on page 64 for
information about audio codec selection. The section “Video
Codec” on page 70 explains video codec selection.
Video Frame Size
Every audience in the output must use the same video frame size to enable the
stream to shift bandwidths during streaming. For instance, a video stream
cannot shift from a 256 Kbps audience at half-VGA dimensions (640x240
pixels) to a 128 Kbps audience at quarter-VGA dimensions (320x240 pixels).
All Audiences Must Encode Video at the Same Dimensions to Allow Rate Shifting
For More Information: See “Frame Size” on page 72 for an
explanation of how to set an output video’s dimensions.
21
22
PART
Part I:
INPUTS AND OUTPUTS
The following chapters explain the basics of how to use
RealProducer to select media inputs and define encoded
outputs.
I
CHAPTER
Chapter 3:
3
INPUTS
The first step for encoding a clip or live broadcast is choosing the
input source. This chapter describes how to select a file or live
capture device as the input. It also explains how to save your
encoding settings to reuse later.
Input Tab
Click the Input tab to display the controls that allow you to select content and
apply prefilter options.
Input Tab
The controls on the the Input tab allow you to do the following:
• Start
a new job (see “Jobs and Job Files” on page 26).
25
• Select
a file to encode (see “File Input” on page 27).
• Capture
• Select
• View
live input (see “Capture Input” on page 29).
a portion of a video to encode (see “Timeline Editor” on page 33).
properties of the input streams (see “Source Properties” on page 35).
• Modify the input using prefilters (see “Audio and Video Preprocessing” on
page 37).
Note: The settings advisor may also display above the Input tab
if RealProducer detects problems with the encoding settings.
The section “Settings Advisor” on page 130 explains this
feature.
Jobs and Job Files
Whenever you use RealProducer, a job records the encoding settings you’ve
selected. You can view the job syntax at any time by clicking the XML tab. If
you save the job to a job file (file extension .rpjf .), you can later use your
encoding settings for another clip or broadcast.
To save a job file, select File>Save, Ctrl+s, or the Save button— —on the
toolbar. If no job file exists for the job, use the save dialog to choose the job
file name and location. You can also choose File>Save Job As to save a modified
job file under a new name. If you want to start over, create a new job by
selecting File>New, Ctrl+n, or the New button — —on the toolbar.
Warning! Creating a new job resets any encoding information
already entered into the graphical interface.
Tip: You can create a job file that defines outputs and
encoding settings, but no inputs. This allows you to create a
library of job profiles to use later.
Note: RealProducer provides predefined job files in the
samples/jobs subdirectory under the RealProducer main
directory.
For More Information: For an explanation of the job file syntax,
refer to RealProducer Command Line and Job File Reference.
26
CHAPTER 3: Inputs
Loading an Existing Job
To open an existing job file, select File>Open, Ctrl+o, or the Open button— —
on the toolbar. Use the browse dialog to navigate to the job file on your file
system. Note the following about reusing a job file:
• RealProducer records any changes you make to the open job, but does not
write the changes into the job file until you save the job.
• Relative
paths in job file values are relative to the directory that holds the
job file.
• Double-check
the audience settings for the job to ensure that you are
encoding the output properly.
For More Information: See “Encoding Settings” on page 50.
• A job file can record information
specific to a certain clip (metadata). You
may need to change this information each time you encode a new clip
using an existing job file.
For More Information: See “Metadata” on page 57.
Upgrading Older Job Files
RealProducer 13.1 uses the job file 3.0 format. The older, version 2.0 job file
format used with earlier versions of RealProducer and RealProducer is not
compatible with the 3.0 format. However, RealProducer 13.1 automatically
updates these older job files to the new 3.0 format.
Warning! Once existing job files are updated to the 3.0 format,
they are no longer compatible with earlier versions of Helix
Mobile Producer and RealProducer.
File Input
Source files are digitized media files on a hard disk, network, CD, or DVD. To
encode output from an existing source, click the File radio button under Input
Source on the Input tab. Then click the Open button— —next to the Input
File field to navigate to the file. After a video file loads, the video preview
region of the Input tab displays the video’s first frame.
27
Input File
Tip: The Input File drop-down records the locations of previous
inputs. Click the drop-down arrow to select from these files.
For More Information: You can set a video clip’s starting and
ending points using the timeline editor. See “Timeline Editor”
on page 33.
Video Source File Size Limit
Some computer file systems limit a single file to 2 GB (2048 MB) in size. At a
320-by-240 size and 15 fps, this is about 9.5 minutes of uncompressed,
digitized video. Certain video production programs support the OpenDML
(AVI 2.0) standard, which allows the creation of files larger than 2 GB.
RealProducer may be able to accept a video source file larger than 2 GB as
input, depending on the production software used to create the file.
If you plan to produce long videos or videos with large dimensions, check
whether or not your video production software is limited to a 2 GB output file
size. If it is not limited to 2 GB, create a video file larger than 2 GB and test it
to determine if RealProducer can accept the file as input.
Disk Space Requirements for Video Capture
Use the following formula to calculate the approximate size in megabytes of a
digitized video file:
(pixel width) x (pixel height) x (color bit depth) x (fps) x (duration in seconds)
8,000,000
Suppose you want to capture a three-minute video at 15 frames per second,
with 24-bit color, in a window that is 320 by 240 pixels. As you can see from
the following equation, your digitized source file would be approximately 622
MB:
(320) x (240) x (24) x (15) x (180) / 8,000,000 = 622 Megabytes
28
CHAPTER 3: Inputs
If necessary, you can conserve disk space by decreasing the clip dimensions or
lowering the frame rate, or both.
Capture Input
To encode live audio or video from a capture card, click the Device radio
button under Input Source on the Input tab. Next, select the audio or video
device to capture from in the Audio or Video drop-down menu.
Input Device
Tip: If you use a single video capture card to capture both
audio and video, choose that card in both the Audio and Video
menus.
Note: If the video capture card is functioning, the video
preview region of the Input tab displays the real-time input.
Audio input is not rendered, however.
For More Information: If you plan to broadcast the captured
input, refer to “Live Broadcasting” on page 87. The section
“Video Recording” on page 161 provides tips for shooting a
video.
Input Duration
By default, RealProducer stops encoding the input when the job is stopped
manually. Check the Duration box to set a specific point in the stream at
which encoding ends. Then enter the time in days (d ), hours (h ), minutes (m ),
and seconds (s ).
Note: This stream duration is measured from the time at
which RealProducer starts the encoding process.
29
Audio Mixer
To launch your operating system’s audio mixer, click and hold the Audio
button. Then choose Recording Mixer from the pop-up menu.
Audio Mixer Context Menu
This opens the recording control window in which you can specify how audio
is mixed.
Audio Mixer
Note: Audio mixer controls are specific to the sound card and
operating system.
Audio Vendor Controls
If you want to adjust the sound recording capabilities of your audio device,
click and hold the Audio button. Then choose Vendor-Provided Controls from
the pop-up menu.
30
CHAPTER 3: Inputs
Audio Vendor Control Context Menu
This opens the control dialog specific to your audio card and operating
system.
Audio Control Dialog (Specific to Vendor)
For More Information: See also “Audio Capture” on page 157
and “Audio Optimization” on page 159.
Video Settings
To adjust the video recording capabilities, click and hold the Video button
next to the video device name. This displays a submenu of available settings
dialogs, which can vary with each capture device.
Video Vendor Control Context Menu
31
This opens the control dialog specific to your audio card and operating
system.
Video Control Dialog (Specific to Vendor)
Video Capture Dimensions
For most video capture cards, you can select the video dimensions in pixels.
The input dimensions should be at least as large as the dimensions of your
largest output.
For More Information: The section “Frame Size” on page 72
explains the common output dimensions that you can set.
Full-Screen Capture
A common capture size is 320 pixels wide by 240 pixels high. If you have a fast
computer, you can capture full-motion video at the full-screen size of 640 by
480 pixels. Do this only if all of the following are true:
• Your
clips will stream at broadband speeds of 250 Kbps or higher.
• Your
encoded clips will be larger than 320 pixels by 240 pixels.
• You have a video workstation capable of digitizing full-motion, full-screen
video. Consumer-oriented PCs typically cannot handle this large of a load.
Cropping and Resizing
Whenever possible, capture video at the same dimensions and aspect ratio as
your intended outputs. This eliminates the need to crop and resize the video
during encoding, which can require significant processing power. If necessary,
however, you can crop and resize during the encoding process:
32
CHAPTER 3: Inputs
• The
section “Input Cropping” on page 39 explains how to crop the video
input.
• See
“Input Resize” on page 44 for a description of how to resize the input
video.
• Each
output can be resized independently. See “Frame Size” on page 72
for details.
Video Capture Frame Rate
For most lower-bandwidth clips and broadcasts, capture at 15 frames per
second (fps). This is the maximum, recommended frame rate for outputs
lower than 150 Kbps. At speeds higher than 150 Kbps, you can encode up to
30 fps. In these cases, you may want to capture the source input at 30 fps.
Timeline Editor
After you load an input video file, you can use the timeline editor to set
starting and ending points for the encoding job. You can use the timeline
editor, for example, to encode only the first minute from a two-minute input
file. If you do not make changes using the timeline editor, the entire source
file is encoded.
Timeline Editor
33
Tip: The Mark-In and Mark-Out boxes of the File Input section
indicate the selected start and stop times in days (d ), hours (h ),
minutes (m ), and seconds (s ). The Mark-Out time is measured
from the input file’s normal beginning, not from the Mark-In
time. See “File Input” on page 27.
Note: The timeline editor does not play the video or render the
audio.
Timeline Editing Controls
The controls on the timeline editor allow you to set the starting and ending
points for encoding. The editor displays the timline section to be encoded as a
green line.
Back to Start. Cick to move the currently displayed position to
the input clip’s normal starting point.
Back 1 Frame. Click to move the currently displayed position
back one frame. You can also click the left arrow on the
keyboard.
Current Position. Shows the position of the frame currently
displayed in the editor. Drag to change the displayed frame.
Forward 1 Frame. Click to move the currently displayed
position forward one frame. You can also click the right arrow
on the keyboard.
Forward to End. Click to move the currently displayed
position to the input clip’s normal end.
Start Point for Encoding. Drag to set the timeline position
where encoding begins.
End Point for Encoding. Drag to set the timeline position
where encoding ends.
Tip: If you open a new video clip as the source, the encoding
markers retain their positions unless the new clip is shorter
than the selected timespan.
Note: RealProducer may adjust the starting and ending points
slightly to align them with input video frames.
34
CHAPTER 3: Inputs
Source Properties
After you select an input file or capture device, the Source Properties region of
the Input tab displays the input’s audio and video properties.
Input Properties
Information displayed for the source properties includes the following:
• duration
of the input source (file only)
• name
of the input (file only)
• audio
format
• number
of audio channels
• audio
bit depth
• video
format
• video
frame rate in frames per second (fps)
• video
frame size in pixels
35
36
CHAPTER
Chapter 4:
PREFILTERS
4
Prefilters modify the input stream before it is encoded. They can
crop and resize the input as well as improve the audio and video
quality. However, some prefilters can significantly increase the
encoding time, which may be problematic during a live broadcast.
Audio and Video Preprocessing
Prefilters appear in the Audio/Video Preprocessing section of the Input tab. All
prefilters are optional.
Prefilter Settings
37
Controls for Displaying and Enabling Prefilters
The following controls appear to the left of each prefilter:
Controls Hidden—A summary of the prefilter settings (if any)
appears to the right. Click to display the full controls.
Controls Displayed—Click to hide the controls.
Prefilter Disabled—Any previous settings are retained for this job,
but the prefilter will not be used during encoding. Click to enable
the prefilter.
Prefilter Enabled—Click to disable the prefilter.
Audio Level
The audio level control allows you to set a decibel gain from +12 (amplify the
audio) to -12 (attenuate the audio).
medium: Audio
use: Boost, decrease, or mute the audio input level.
impact: Negligible. Safe for broadcasts.
To change the audio input level, click and drag the slider control. You can also
type a value directly into the text box or click the arrows. Click Mute Input
Audio if you want to silence the audio track of a video.
Audio Level Controls
Tip: A value of 6 doubles the audio level while a value of 12
quadruples it. A value of -6 reduces the level to half, while -12
reduces it to a quarter.
Note: When you amplify the audio signal, RealProducer
dynamically compresses the audio range if the output signal
becomes overmodulated. This way, the output audio is never
clipped, even at maximum gain.
38
CHAPTER 4: Prefilters
Audio Synchronization
The audio synchronization prefilter corrects audio shift when audio input is
out of synchronization with a video’s visual track.
medium: Audio
use: Shift audio timing to synchronize it with the video track.
impact: Negligible. Safe for broadcasts.
In the prefilter controls, select Advance or Delay. Then set the number of
seconds for the advance or delay by typing the value in the text box or clicking
the arrows.
Audio Synchronization Controls
Tip: Some third-party video editing tools provide information
about how much delay exists between audio and video.
Input Cropping
The cropping prefilter reduces the size of the input by cropping out unwanted
portions along the video edges. This can reduce the amount of data encoded
and boost clip quality.
medium: Video
use: Reduce the size of the input by cropping along the video edges.
impact: Small. Safe to use with live broadcasts.
Tip: If you are encoding a letterbox clip (16:9 aspect ratio) for
display on computer screens that use a traditional 4:3 aspect
ratio, crop out the black bars at the top and bottom of the
video image. This helps to improve the video quality.
For More Information: See also “Cropping and Resizing to
Change Aspect Ratios” on page 74 for an example of how to
alter an input clip’s aspect ratio.
39
Cropping Controls
To crop a video, click the Input Cropping box.
Input Cropping Controls
You can select the cropped area three ways:
• Click
a text box and type the new value manually.
• Click
the arrows beside each text box to select a value.
• Click
and drag the yellow lines in the preview window.
Cropping Values
The following values appear in the cropping control text boxes.
Left Pixels from the left edge where cropping occurs. You can
specify up to 32 pixels less than the total width.
Top Pixels from the top edge where cropping occurs. You can
specify up to 32 pixels less than the total height.
Right Pixels from the right edge where cropping occurs. You can
specify up to 32 pixels less than the total width.
Bottom Pixels from the bottom edge where cropping occurs. You can
specify up to 32 pixels less than the total height.
Note: If the width or height of the cropped video is not a
multiple of 4, the next lower multiple is used. For example, a
value of 162 pixels for width or height is adjusted to 160 pixels.
Cropping Preview
Yellow lines appear on the input preview to indicate the cropped section. You
can click and drag a line to set a new cropping position. Click inside the
selected area to drag the entire cropping section around the video frame. Areas
that will not be encoded are grayed out.
40
Cropped Video Region
De-Interlace and Inverse-Telecine
The de-interlace and inverse-telecine prefilters remove artifacts that may occur
in videos larger than 320x240 pixels and NTSC-format video transferred from
film, respectively.
De-Interlace and Inverse-Telecine Controls
If you need to use these prefilters, click the Automatic radio button to have
RealProducer apply the prefilters only if needed. To use just one of the
prefilters, check the Manual button and select the prefilter (one or both) you
want.
41
Inverse-Telecine Prefilter
Use the inverse-telecine prefilter when encoding NTSC video that was
transferred from film and has a frame rate of 30 fps. The prefilter strips out
redundant fields, letting RealProducer focus on image quality.
medium: NTSC video
use: Remove redundant frames.
impact: Small.
What is Inverse-Telecine?
Film is usually shot at 24 frames per second (fps), whereas the NTSC standard
for video is 30 fps. The film-to-video conversion (called “telecine”) duplicates
some fields to increase the frame rate from 24 to 30. American films
transferred to video, for example, undergo the telecine process. Applying the
inverse-telecine prefilter strips out the redundant frame information,
resulting in a higher-quality streaming video.
Tip: PAL video does not require the inverse-telecine prefilter
because the conversion from 24 fps film to 25 fps PAL does not
use the telecine process.
De-Interlace Prefilter
The de-interlace prefilter removes jaggedness in interlaced NTSC or PAL
video.
medium: NTSC or PAL video
use: Remove jaggedness from video.
impact: Small. Not used if the video is less than 240 lines high.
Generally safe to leave on for all video input.
What is De-Interlacing?
A video camera running at 30 frames per second captures the odd-numbered
lines of a field in 1/60th of a second and the even-numbered lines in the next
1/60th of a second. It then interlaces the two to create the frame.
Because half the field’s lines are captured a fraction of a second later than the
other half, fast-moving objects may appear jagged. This is the result of the
object advancing slightly within 1/60th of a second.
42
Tip: Typical source video for standard-resolution television is
480 lines high. If you digitize the video with a video capture
card that captures at 240 lines high or less, the card throws out
either the odd or the even lines, de-interlacing the video during
the capture process.
De-Interlacing Example
The following figure illustrates jaggedness in a detail of an interlaced video.
Jaggedness in an Interlaced Video (detail)
The next figure shows the jaggedness removed using the de-interlace prefilter.
Jaggedness Removed with the De-interlace Prefilter (detail)
Video Noise
Video noise is a by-product of poor quality in the video production process.
The noise reduction prefilter can help reduce this distortion.
medium: Video
43
use: Eliminate visual artefacts.
impact: Small for Low level. 
Large for High level (not recommended for broadcasts).
Use the drop-down of the noise controls to choose the Low or High level.
Video Noise Controls
Tip: The source of the noise is typically hardware, such as the
video tape, capture card, or camera. Using professional-quality
equipment and media helps eliminate video noise at the
source. If your source video has high quality, you won’t need
the noise reduction prefilter.
For More Information: See “Video Recording” on page 161 for
tips on creating high-quality source video.
Low Noise Filtering
If your video input has a small amount of noise, use the Low setting. Because
this has a small impact on processing power, the Low noise level is generally
safe to leave on for all jobs. It’s better practice, though, to use it only when
necessary because it may slightly degrade high-quality input video.
High Noise Filtering
If noise greatly distorts the source video, try the High noise setting. This
setting may remove slight details, making highly textured surfaces look more
smooth, which may not be desirable in all cases.
Warning! The High noise setting can add 30% or more to the
encoding time.
Input Resize
The resizing prefilter allows you to resize the video before you encode it.
medium: Video
44
use: Resize the video dimensions.
impact: Small for fast resize. High for high-quality resize (not
recommended for broadcasts).
Tip: If the input video has a non-square pixel aspect ratio (such
as DV), you can use the resizing prefilter to shorten the video
horizontally. This converts non-square pixels to square pixels.
For More Information: When you encode multiple outputs, you
can set the video dimensions for each output separately. See
“Frame Size” on page 72.
Resize Controls
Use the resize controls to specify predefined or customized video dimensions.
The video preview window on the Input tab indicates the new video size.
Resize Controls
In the drop-down, you can set one of the following values (WidthxHeight in
pixels):
• Custom —Set
pixel width and height using the Width and Height menus.
• 128x96 (SQCIF) —Sub-Quarter
Common Intermediate Format.
• 176x144 (QCIF) —Quarter
• 352x288 (CIF) —Common
Intermediate Format.
• 640x240 (HVGA) —Half
VGA.
• 320x240 (QVGA) —Quarter
VGA.
Note: The minimum size for a resized video is 32-by-32 pixels.
The width and height must be multiples of 4, such as 160
pixels, 240 pixels, and so on.
Tip: If you plan to create multiple outputs at different sizes, set
the input size to the largest output size. Then scale other
45
outputs smaller as needed. The section “Frame Size” on page
72 explains how to resize a specific output.
Maintain Aspect Ratio
When the Maintain Aspect Ratio box is checked, you can enter just the height
or width value for the resize. RealProducer automatically calculates the other
value to maintain the ratio between the two dimensions. By unchecking this
box, you can enter width and height values independently.
Warning! If you do not maintain the aspect ratio, the output
may appear distorted.
High-Quality Resize
Selecting a high-quality resize results in a superior image. However, it may
double or triple the encoding time because it carefully analyzes the video
source before resizing.
Warning! Because of its potentially high impact on encoding
performance, the high-quality resize prefilter is not
recommended for live broadcasts.
Black-Level Correction
Black-level correction improves a video’s contrast by making near-black pixels
pure black and near-white pixels pure white. This improves the video’s
appearance if it looks washed out because of a lack of contrast.
medium: Video
use: Improve visual contrast.
impact: Small. Generally safe to leave on for all video input.
Note: You need only to enable the black-level prefilter to use it.
It has no other controls.
Tip: Applying this prefilter to the input can improve codec
efficiency by increasing the number of pixels that have the
same color value, allowing for greater compression.
46
CHAPTER
Chapter 5:
5
OUTPUTS
Output options allow you to configure encoding settings and send
the stream to a file, a broadcast server, or both.
Output Tab
Click the Output tab to display the controls that allow you to define your
encoding outputs and destinations.
Output Tab
The controls on the Output tab allow you to do the following:
• Set
up one or more outputs (see “Outputs List” on page 49).
• Define
encoding settings for each output using audiences (see “Encoding
Settings” on page 50).
• Save
each output to a file (see “Output File Destination” on page 55).
47
• Deliver
an output stream to a broadcast server (see “Server Destinations”
on page 103).
• Add
clip information to each output (see “Metadata” on page 57).
Note: The settings advisor may also display above the Output
tab if RealProducer detects problems with the encoding
settings. The section “Settings Advisor” on page 130 explains
this feature.
Single Outputs and Multiple Outputs
Each output defines a set of encoding options such as the file type and which
audio and video codecs are used. One output may suit all of your target media
players. However, you can also define multiple outputs. For example, you
might use one output to encode the input at 320x240 pixels using the
RealVideo 10 video codec. Another output can encode the same input at
176x132 pixels using the RealVideo 8 video codec.
Note: Each output you add to a job increases the processing
time required during encoding.
Outputs and Destinations
The data for each output is delivered to at least one destination. There are two
types of destinations: a file destination and a broadcast server destination. For
example, to broadcast a live event while simultaneously writing the stream to
an archive file, you set up both a server destination and a file destination. For
each encoding job, RealProducer can encode one or more outputs, and each
output can have one or more destinations.
48
CHAPTER 5: Outputs
Multiple Outputs Written to Multiple Destinations
Tip: Outputs define what you are encoding. That is, the output
sets the file type, screen size, streaming bit rate, and codecs
used. A destination defines where the output is delivered, either
to a file or to a broadcast server.
For More Information: See “Output File Destination” on page 55
and “Server Destinations” on page 103.
Outputs List
For each encoding job, you define at least one output by adding the output to
the Outputs List.
Outputs List
49
You add and delete outputs from the job using the buttons at the top of the
Outputs List:
Add a new output to the Outputs List.
Delete the selected output.
Output Selection
Clicking the Add button—
RealMedia output.
—displays a menu allows you to choose a new
Note: The other sections on the Output tab display the
information only for the selected output. You can select and
edit only one output at a time. When you encode the job,
however, all outputs are encoded simultaneously.
Output Name
When you add an output, RealProducer creates a default name for the output
in the Outputs List. Change the name by clicking the default name in the
Outputs List and entering a new name.
Note: Output names are for your convenience in identifying
the output. They do not affect the encoding process. Choose
names that clearly identify each output’s intended viewers.
Encoding Settings
In the Encoding Settings section of the Output tab, you set the basic encoding
parameters by adding one or more audiences to the selected output.
Encoding Settings Section (Multi-Rate RealVideo Clip)
50
CHAPTER 5: Outputs
Note: If you are encoding multiple outputs, highlight the
correct output in the Outputs List before choosing an audience.
You can add audiences to one output at a time.
Audience Control Buttons
The buttons to the right of the Encoding Settings section allow you to manage
the audience templates that define the output’s encoding parameters:
Add an audience template to the selected output.
Edit the encoding settings for the selected audience.
Save As a new audience template.
Delete the selected audience from the output.
Audience Templates
Each audience defines a set of encoding parameters, such as the streaming bit
rate and the codecs used to compress the stream. Click the Add button— —
to add an audience to the output. The pop-up dialog displays the available
audience templates.
Audience Template Pop-Up
51
Select the audience name and click Add to Job. The Encoding Settings section
then displays the audience, listing its encoding properties.
Tip: Using the preferences, you can select audiences that are
used automatically whenever you create an output. See
“Output Preferences” on page 138.
For More Information: The section “Predefined Audience
Templates” on page 145 lists the properties of the predefined
audience templates included with RealProducer.
Multiple Audiences for Multi-Rate Clips
A RealMedia output can include multiple audiences to create a multi-rate
streaming clip or broadcast. To select more than one audience, hold down the
Ctrl key and click the audience names. You can also add each audience to the
output one at a time.
Tip: Including multiple audiences in a clip intended solely for
downloading increases the file size unnecessarily and does not
improve the playback quality.
For More Information: For background on using multiple
audiences to enable rate shifting during streaming, refer to
“Multi-Rate Streams” on page 18.
Name Matching
You can filter the templates shown in the audiences pop-up by typing a text
string in the Where name matches field. Only audience names that contain the
text then display. For example, enter 80 to show the audiences designed to
stream at 80 Kbps.
Tip: Text matching is not case sensitive.
Audience Customization
In many cases, you may need to modify the settings for an audience added to
an output. For instance, you may want to increase the streaming bandwidth,
or encode a soundtrack using a different audio codec. To modify an audience,
highlight the audience name in the Encoding Settings section and click the Edit
button— . This displays the Encoding Settings pop-up.
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CHAPTER 5: Outputs
Audience Encoding Settings Pop-Up
Audience Properties
In the Encoding Settings pop-up, you can change the following values:
• The
template name in the Name field.
• Audio
options such as the audio codec, audio bit rate, and output
sampling rate. (See “Audio Encoding Settings” on page 63.)
• Video
options such as the video codec, video bit rate, and output clip
dimensions. (See “Video Encoding Settings” on page 69.)
• Advanced
video options such as the maximum preroll and the use of
variable bit rate (VBR) encoding. (See “Advanced Video Settings” on page
77.)
Template Creation
Customizing an audience’s properties applies the changes to the current job
only. It does not modify the original audience template. To preserve the
customizations so that you can apply them quickly to other jobs, highlight the
audience name in the Encoding Settings list. Then click the Save As button—
.
53
Save Audience Template
In the Save as Template pop-up, do one of the following:
• To
update the original template with the new settings, click Save and
confirm that you want to replace the existing template.
• To
create a new template, enter a new name in the Template Name field.
Then click Save.
Tip: If you already entered a new name in the Name field of the
Encoding Settings pop-up, RealProducer prompts you to save
the template under that name.
Note: Templates are stored in the audiences subdirectory of the
RealProducer installation directory using the template name
along with the file extension .rpad .
For More Information: For more about audience file syntax, refer
to RealProducer Command Line and Job File Reference.
Template Deletion
Do the following to delete an audience template permanently:
1. Click the Add button— —in the Encoding Settings section of the Output
tab to display the audience template pop-up (see “Audience Templates” on
page 51).
2. In the list of templates, select the audience that you want to delete.
3. Click the Delete button—
—on the right side of the audience pop-up.
4. Confirm the deletion.
Tip: If the audience is still included in the output, highlight
the template name in the Encoding Settings list and click the
Delete button— . This removes the audience settings from
the job.
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CHAPTER 5: Outputs
Output File Destination
In the Output File section, you can create a file destination for the selected
output. Click the Open button— —to navigate to a location on the file
system where you want to write the file. Enter a file name, then click Save in
the dialog.
Output File Section
To the right of the file destination section, the Avail Space on Disk field
indicates the free space in Gigabytes on the selected disk.
Tip: Using the preferences, you can select a clip name that is
used automatically whenever you create a file destination. See
Note: With RealMedia clips, the options for progressive
download and stream hinting are always enabled.
For More Information: You can send live input to a server for
broadcast while simultaneously writing it to a file for archive
purposes. The data sent to each destination is identical. See
“Server Destinations” on page 103.
Archive Clips
When setting the output file name, you can quickly select the output directory
and file name of a previous file by clicking the file name drop-down arrow.
RealProducer does not overwrite the previous clip if it still exists. Instead, it
archives the existing clip by appending _archNNN to the base file name.
For example, movie.rm becomes movie_arch001.rm before the new movie.rm clip
is saved. If you encode the output again, the existing movie.rm becomes
movie_arch002.rm . Higher numbers therefore represent newer archives.
Output File Extension
The output file extension depends on the output type (see “Output Selection”
on page 50). RealMedia CBR clips use the .rm extension. RealMedia VBR clips
55
typically use the extension .rmvb . Mobile media players may not recognize the
.rmvb extensions, however. In this case, encode VBR output using the .rm
extension.
Two-Pass Encoding
When the Two Pass option is enabled, RealProducer runs through the entire
source clip once to gather information about the source stream. In the second
pass, it performs the actual encoding. Two-pass encoding can substantially
increase clip quality, especially for VBR clips, but it requires more encoding
time.
Tip: Use two-pass encoding whenever you encode from a
digitized file. Turn it off only if you must decrease the
encoding time.
Note: Two-pass encoding cannot be used during live
broadcasts. It is automatically disabled if you add a server
destination to the output.
For More Information: For more about VBR encoding, refer to
“Variable Bit Rate Video” on page 78.
Output File Size
An encoded, compressed clip is often smaller than the input file. This means
that file size limits imposed by an operating system’s file system are generally
more of a problem when capturing video than when encoding it. However,
there are some cases in which an output clip may exceed the operating
system’s maximum:
•A
clip encoded for multiple bandwidths (especially with multiple, highspeed audiences) may exceed the source clip in size, even though each
stream contains less data than the original input.
• If
you encode a long video clip directly from a live source or capture
device, the encoded clip may grow larger than the allowable file system
limit.
For More Information: See “Disk Space Requirements for Video
Capture” on page 28.
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CHAPTER 5: Outputs
RealMedia File Rolling
When a RealMedia clip reaches the operating system’s file size limit,
RealProducer automatically creates, or rolls, a new clip. The new clip has the
same name as the original clip, but with a number added to the file name. For
example, movie.rm rolls to movie1.rm when movie.rm reaches the operating
system limit. The clip movie1.rm rolls to movie2.rm if it grows too large, and so
on.
For More Information: By using the command-line application
or editing a job file, you can set lower limits on file rolling. You
can also roll files by time, such as every 15 minutes. For details,
refer to RealProducer Command Line and Job File Reference.
Metadata
RealProducer can encode metadata such as title, author, and copyright
directly into an output stream. To define metadata for an output, highlight
the output in the Outputs List. Then use the controls in the Metadata section.
Metadata Section
Metadata Buttons
Use the buttons to the right of the Metadata section to define the selected
output’s metadata values:
Add a metadata entry to the output.
Edit the selected metadata value in a pop-up. You can also
double-click the metadata line to display the pop-up.
Copy the selected metadata value to a different output. Click
the button, then use the context menu to select a specific
output or all outputs.
Delete the selected metadata entry.
57
Tip: Using the preferences, you can select metadata values that
are used automatically whenever you create an output. See
Metadata Entry
You add or edit metadata values in the Edit Metadata pop-up. When you add a
value, select the type of metadata in the Name pull-down. Then enter the
metadata value in the Value field. When you edit a value, you can change only
the Value setting.
Edit Metadata Pop-Up
Tip: When adding or editing metadata, you can quickly choose
a previous value for the selected metadata type by clicking the
Value field drop-down arrow.
Metadata Titles and Values
The following sections list the acceptable metadata values.
Title
Short title of the content.
Author
The name of the person or organization that created the content.
Copyright
The copyright string, such as:
(c) 2009 XYZ Corporation
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CHAPTER 5: Outputs
Keywords
Words that search engines can read to categorize the clip. Add a few words,
separated by spaces, that will help your audience search for your clip.
Tip: Unless you are adding a proper name, use lowercase for
each term. Avoid overly generic terms such as video or music .
Description
Description of the content that appears when the viewer displays extended
clip information. This value is used to provide detail too long for the title.
Rating Criteria
A ratings value that indicates content suitability for different age groups. The
values vary depending on the ratings entity.
RealMedia Ratings Criteria
RealPlayer uses the following ratings values to indicate content suitability for
different age groups:
• No Rating (default)
• All Ages
• Older Children
• Younger Teens
• Older Teens (15 and up)
• Adult Supervision Recommended
• Adults Only
59
60
PART
Part II:
ADVANCED AUDIO AND VIDEO SETTINGS
The chapters in this section explain how to customize audio and
video settings to tailor outputs to your specific needs.
II
CHAPTER
Chapter 6:
AUDIO CUSTOMIZATION
6
Using the audio customization options, you can modify the audio
encoding properties of an audience. You can select the audio codec,
bit rate, and sampling rate.
Audio Encoding Settings
You customize audio by selecting the audience in the Encoding Settings section
of the Output tab, then clicking the Edit button— . The Audio section of the
audience pop-up displays the audio editing options.
Audio Encoding Settings
Note: If you are working with a multi-rate output, you can
customize the audio settings for only one audience at a time.
For More Information: See “Audience Customization” on page
52.
63
Audio Codec
The Codec drop-down allows you to choose a specific type of codec for audio
encoding.
use: Select the audio codec.
restrictions: Output type restricts the available codecs (see “Output Selection”
on page 50). All audiences for a rate-shifting clip must use the
same audio codec.
Choices include the following:
• None —Do
not encode audio.
• RealAudio —Mono,
•
stereo, stereo surround, or multichannel music. See:
“RealAudio Mono Music Codecs” on page 15.
• “RealAudio
Stereo Music Codecs” on page 15.
• “RealAudio
Stereo-Surround Codecs” on page 16.
• “RealAudio
5.1 Multichannel Audio Codecs” on page 16.
• RealAudio Voice —Voice.
See “RealAudio Voice Codecs” on page 13.
• RealAudio High Response —Mono
or stereo music. See “RealAudio High-
Response Codecs” on page 14.
Channels
The Channels drop-down sets the number of audio channels encoded.
use: Select the number of channels encoded.
restrictions: Codec choice affects the number of channels that may be encoded.
Choices, which depend on the chosen codec’s capabilities, may include the
following:
• Mono
• Stereo
• Stereo Surround
• 5.1 Multichannel
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CHAPTER 6: Audio Customization
What is Stereo Surround?
Stereo surround audio includes additional channels that are mixed (or
matrixed) using the conventional left and right stereo channels. The extra
channels can be played using a stereo-surround receiver. However, stereo
surround is compatible with any stereo receiver. If the receiver cannot extract
the data for the extra channels, it plays just the stereo left and right channels.
For More Information: You can find additional information
about stereo surround input at http://www.dolby.com. or
http://www.dts.com/.
Stereo Surround Channel Arrangements
The following table explains the common channel arrangements found in
matrixed, stereo surround audio.
Common Channel Arrangements in Matrixed, Stereo Surround Audio
Channels
Description
4
To the standard left and right channels, this arrangement adds a front
center and a rear center channel.
5.1
This type of matrixing uses five main channels: left, center, right, left
surround, and right surround. The “.1” refers to a sixth, low-frequency
effects (LFE) bass channel that covers a fraction of the frequency range of
the main channels.
6.1
Building on the 5.1 arrangement, this type of matrixing adds two
additional channels for playback on two additional speakers.
7.1
Also building on the 5.1 arrangement, this type of matrixing adds four
additional channels for playback on two additional speakers.
When to Use a Stereo-Surround Codec
Stereo surround is suitable for high-bandwidth streaming or download
audiences listening on more than two speaker channels (home theater, for
example). You should encode your audio using a stereo-surround codec if all
of the following are true:
• The
source audio is matrixed, multiple-channel sound. (These sources are
prevalent on DVDs and television broadcasts.)
• At
least some of your listeners will play the output on systems that have
more than two speaker channels.
65
• You
are targeting a high-bandwidth streaming or download audience.
Tip: Because the multi-channel input of stereo surround is
actually encoded as standard stereo input, the computer
running RealProducer does not require a special sound card or
cabling.
When Not to Use a Stereo-Surround Codec
Encode your audio using a standard stereo codec if any of the following are
true:
• The
input is standard stereo (left and right channels with no additional,
matrixed channels).
Note: Although you can encode standard stereo input using a
stereo-surround codec, there are no advantages to doing so.
RealProducer does not create the extra channels. It only
preserves existing channels. Additionally, standard stereo
codecs are more efficient than stereo-surround codecs at
encoding two-channel audio.
• Your
audience will play the stream on systems that includes only the
stereo left and right channels.
• You
wish to stream the audio at a bandwidth lower than those available
with stereo-surround codecs.
Tip: When you create a SureStream RealAudio clip, you can
encode low-bandwidth streams in conventional stereo, and
high-bandwidth streams that preserve the stereo surround
audio.
What is Multichannel Audio?
Multichannel audio includes channels in addition to the left and right stereo
channels. Unlike stereo surround, however, multichannel audio encodes the
additional channels separately. Multichannel audio is suitable for highbandwidth streaming or download audiences listening on more than two
speaker channels (home theater, for example).
Tip: Multichannel audio is often called discrete multichannel,
whereas stereo surround is called matrixed multichannel. The
quadraphonic multichannel format, which uses two front and
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CHAPTER 6: Audio Customization
two back channels, is obsolete and not supported by
RealProducer.
Sounds Cards for Multichannel Audio Input
To enable discrete, multichannel audio, your sound system must capture and
preserve each channel. For live capture, the sound card on the RealProducer
computer must support the multiple input channels. A standard sound card
supporting only two-channel stereo input cannot capture multichannel audio.
Tip: A common audio format to use with multichannel audio
is AC-3, which is also called Dolby Digital.
Channels Encoded by RealProducer
RealProducer encodes all multichannel output as 5.1 channels (left, center,
right, left surround, right surround, LFE bass) or 6 channels. It can accept
fewer than six channels as input, upmixing as necessary to create the
additional channels.
Multi-Rate Clips with Standard Stereo for Low Bandwidths
When encoding a SureStream RealAudio clip, you can encode multichannel
audio at high bandwidths and standard stereo at low bit rates. Do not encode
standard stereo input with the multichannel codecs, however, as the quality
will not be as high as when you use standard stereo codecs.
Average Bit Rate
In the Avg. Bitrate field, use the drop-down to select the bit rate for the audio
stream.
use: Set the audio stream bit rate.
restrictions: Codec and channels settings affect possible choices.
For More Information: See “Audio Codec Choices” on page 13.
67
Sample Rate
The Sample Rate field indicates the sampling rate of the output. RealAudio
codecs support just one sampling rate.
use: Indicate the audio output sampling rate.
restrictions: none
What is a Sampling Rate?
An audio sampling rate indicates the number of samples taken every second
when the analog audio signal was digitized. Input audio from a file or audio
capture card has a specific sampling rate, typically within the range of 8,000 to
48,000 Hz.
Each audio codec also has an optimal sampling rate (or rates). If the input
audio’s sampling rate does not mach the codec’s required rate, RealProducer
resamples the input. This changes the sampling rate to that required by the
codec without causing pitch shifting.
For best results, the audio input sampling rate should be equal to or greater
than the codec’s rate. For rate-shifting clips, the input sampling rate should be
equal to or greater than the highest overall sampling rate used. This is
typically the sampling rate used by the highest-bandwidth audience chosen.
Tip: During a live broadcast, it is helpful to avoid resampling
by ensuring that your audio input uses a preferred sampling
rate of the output.
For More Information: The audio properties, which are described
in “Source Properties” on page 35, display the input sampling
rate. The section “Audio Codec Choices” on page 13 lists the
optimal sampling rate for each audio codec.
68
CHAPTER
Chapter 7:
VIDEO CUSTOMIZATION
7
Video customizations allow you to modify the video encoding
properties of an audience. For example, you can select the video
codec, the bit rate, and the frame rate. You can also scale the output
video smaller than the input video.
Video Encoding Settings
You customize video settings by selecting the audience in the Encoding Settings
section of the Output tab, then clicking the Edit button— . The Video section
of the audience pop-up displays the video editing options.
Video Encoding Settings
customize the video settings for just one audience at a time.
69
52.
Video Codec
The Codec drop-down sets the video codec used.
use: Choose the video codec.
restrictions: All audiences for a rate-shifting clip must use the same codec.
For standards-based codecs, the profile is included with the codec name.
Select one of the following:
• None —Do
not encode video.
• RealVideo 8 —See
“RealVideo 8 Codec” on page 18.
Level
The Level drop-down is not functional for RealVideo content.
Video Average Bit Rate
For the Avg. Bitrate option, use the arrows to select the average bit rate for the
video stream in Kilobits per second (Kbps).
use: Set the video stream average bit rate.
restrictions: None.
Note: The total bit rate for the audience equals the audio bit
rate plus the video bit rate: Total Bit Rate = Audio Bit Rate +
Video Bit Rate .
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CHAPTER 7: Video Customization
Frame Rate
Use the arrows of the Frame Rate option to set the maximum frame rate for
the video stream.
use: Set the video maximum frame rate.
restrictions: Output frame rate will not exceed the input frame rate (see “Source
Properties” on page 35).
Target Frame Rates
The higher the frame rate, the smoother the motion in the video.
24 to 30 Frames Per Second
The standard frame rate for full-motion video is 24 to 30 fps. At this speed,
the human eye perceives movement as continuous—a phenomenon known as
persistence of vision.
Tip: RealNetworks recommends using a rate of 30 fps only for
download clips or if streaming bandwidth is at least 250 Kbps.
15 Frames Per Second
This is a common frame rate target for video that streams at less than 250
Kbps. To most people, a 15 fps video appears to flow relatively smoothly.
Below 15 Frames Per Second
You can set a frame rate target below 15 fps for lower-bandwidth settings.
Below 7 fps, the video will look very jerky. Below 3 fps, a video essentially
becomes a slideshow.
Tip: Devices with slow processors may have trouble decoding
video with a high frame rate. For these devices, you may want
to choose a slower maximum rate, such as 7.5 fps, even if the
available bandwidth supports a higher frame rate.
Factors that Affect RealVideo Frame Rates
For RealVideo output, the frame rate field sets only the maximum frame rate.
The actual frame rate for an encoded video varies throughout the clip. Several
factors affect how the encoded frame rate of the RealVideo output.
71
Video Dimensions
The video’s dimensions greatly affect frame rate. If the dimensions are too
large for your target bandwidth, you will not get a high frame rate.
Tip: To get a higher frame rate, reduce the output video
dimensions as described in “Frame Size” on page 72.
Codec Choice
RealVideo 10 generally provides a frame rate faster than that produced by
older RealVideo codecs.
Tip: RealVideo has an option for smoother motion. At lower
bandwidths, this helps to raise the clip’s overall frame rate. See
“Frame Rate Mode” on page 76.
Two-Pass Encoding
Using this option helps RealProducer analyze the input better and produce
the highest frame rate possible.
For More Information: See “Two-Pass Encoding” on page 56.
Variable Bit-Rate Encoding
In a video that has a mix of fast and slow scenes, VBR encoding helps the fast
scenes achieve a higher frame rate.
For More Information: See “Variable Bit Rate Video” on page 78.
Frame Size
By default, the encoded video has the same dimensions as the video input. To
change the size of the output, use the Frame Size controls.
use: Change the output video dimensions.
restrictions: For a multi-rate RealMedia clip, all audiences must encode video
output at the same frame size.
72
Frame Size Controls
In the Frame Size drop-down, you can set one of the following values
(WidthxHeight in pixels):
• No Resize —Keep
• Custom —Set
output size the same as input size.
pixel width and height using the WxH text fields.
• 176x144 (QCIF) —Quarter
• 352x288 (CIF) —Common
Intermediate Format.
• 640x240 (HVGA) —Half
VGA.
• 320x240 (QVGA) —Quarter
VGA.
Maintain Aspect Ratio
If you check the Maintain Aspect Ratio box, you can enter just the height or
width value for the resize. RealProducer automatically calculates the other
value to maintain the ratio between the two dimensions. By unchecking this
box, you can enter width and height values independently.
Warning! If you do not maintain the aspect ratio, the output
may appear distorted.
High-Quality Resize
Selecting the Use High Quality Resize option produces superior results, but
increases the encoding time. Uncheck the box if you need to decrease the
encoding time, such as during a live broadcast. Note that the video quality will
decline, however.
Notes on Resizing
Note the following when resizing video output.
Methods of Resizing
There are three methods of resizing available:
73
• capture
card
When capturing live input, use the video capture card to set the video
input to the same dimensions as the largest output size. This is generally
faster than resizing input through software.
• resizing
prefilter
The resizing prefilter (see “Input Resize” on page 44) resizes the input,
whether a live capture or a prerecorded file, before it is encoded. If you
want all of your outputs to be the same size, resize the input using this
prefilter.
• video
output
If you are encoding multiple outputs at different dimensions, define each
dimension in the video settings of each output.
Cropping and Resizing to Change Aspect Ratios
Often, a source video is captured at a 4:3 aspect ratio, but must be encoded for
a mobile device that uses a different aspect ratio. To change the aspect ratio
without distorting the output, follow these steps:
• Use
the input cropping prefilter (see “Input Cropping” on page 39) to
crop the video to the device’s screen aspect ratio.
• Resize
the output to the device’s screen size while maintaining the aspect
ratio.
Cropping and Resizing Example
The following figure illustrates a 320x240 input video cropped to 292x240,
then resized to 176x144.
Video Cropped and Resized
74
Desktop Video Dimensions
Most desktop videos use the 4:3 aspect ratio of standard computer monitors
or the 16:9 aspect ratio of widescreen monitors. The following table provides
size recommendations based on bandwidth.
Recommended Video Dimensions
Bandwidth
Pixel Dimensions (4:3)
Pixel Dimensions (16:9)
less than 256 Kbps
176x132 ; 240x180
192x108 ; 256x144
256 to 512 Kbps
320x240 ; 448x336
320x180 ; 512x288
786 Kbps or higher
448x336 ; 640x480
768x432 ; 1280x720
Note: At larger dimensions such as 640x480 , the input video
should be of very high quality.
Encoding Complexity
The encoding complexity affects how the codec analyzes the input before
encoding it. The higher the complexity, the better the quality of the output.
use: Determines how complexly the codec encodes the output.
restrictions: Higher complexities require more processing time.
In the Encoding Complexity drop-down, select one of the following complexity
modes:
• Very Low (Fastest)
• Low (Faster)
• Medium
• High (Slower)
• Very High (Slowest)
Tip: The terms Fastest , Faster, Slower, and Slowest refer to the
relative speeds of the encoding process that you can expect
when you choose one of these complexity levels.
Note: For RealVideo, Very Low and Low are equivalent settings.
As well, the High and Very High settings produce the same
results.
75
Frame Rate Mode
The Frame Rate Mode option affects how the RealVideo codec encodes scenes
when available bandwidth is tight.
use: Emphasize smooth motion or picture clarity.
restrictions: Primarily affects low-bandwidth encodings.
In the drop-down, choose one of the following:
• Sharp —Focus on image quality, sacrificing smooth motion by lowering the
frame rate if necessary.
• Normal —Compromise
• Smooth —Keep
between image quality and smooth motion.
the frame rate as high as possible, sacrificing image clarity
as necessary.
• Slideshow —Encode
as a slideshow of still frames.
Tip: A slideshow is recommended only for very large videos
encoded for very low bandwidths. It is better practice, however,
to resize the video to dimensions appropriate for you target
audience.
76
CHAPTER
Chapter 8:
ADVANCED VIDEO OPTIONS
8
Using advanced video options, you can create a variable bit rate
(VBR) clip for download or streaming. You can also modify the
stream preroll and video key frame interval.
Advanced Video Settings
You can set advanced video options by selecting the audience in the Encoding
Settings section of the Output tab, then clicking the Edit button— . The
Advanced Video Settings section of the audience pop-up displays the available
options.
Advanced Video Encoding Settings
customize the advanced video settings for only one audience at
a time.
77
52.
Variable Bit Rate Video
Click Perform Variable Bit Rate Encoding to create a VBR clip. If this option is
not used, the output is a CBR clip that can have one or more audiences.
use: Create a download or streaming clip that can exceed the average
bandwidth setting.
restrictions: Only one audience for each VBR output.
Tip: Two-pass encoding is an important component for
creating a high-quality VBR clip. For more information, refer
to “Two-Pass Encoding” on page 56.
VBR Compared to CBR
A video clip streams at either a constant or a variable bit rate:
• CBR
(Constant Bit Rate)
CBR encoding is the traditional mode for streaming video. You should
generally use CBR video when streaming at bandwidths below 350 Kbps,
or anytime you want to create a rate-shifting clip.
• VBR
(Variable Bit Rate)
VBR encoding gives more bandwidth to scenes that are hard to compress,
making the most visible difference in videos that have fast-moving, highaction scenes. VBR encoding is well-suited for the following
circumstances:
• High-quality
• Streaming
download clips.
at bandwidths of 350 Kbps or higher with no rate shifting.
VBR encoding is not suited for the following situations:
• Live
broadcasts.
• Streaming
• Encoding
78
at bandwidths below 350 Kbps.
a multi-rate clip that allows rate shifting.
CHAPTER 8: Advanced Video Options
Networks Suitable for VBR Streaming
To accommodate VBR, the streaming network must be able to handle the
bandwidth spikes inherent in VBR encoding. The following types of audience
networks are good candidates for VBR streaming:
• Local
area networks (LANs) such as a corporate network.
• Cable
modem users
Because all viewers in these networks share a large pool of bandwidth, a VBR
clip’s intermittent bandwidth spikes tend not to overload a single viewer’s
connection bandwidth.
Networks Less Suitable for VBR Streaming
Connections in which bandwidth is not shared, such as DSL, can prove
problematic for VBR streaming. A 450 Kbps VBR clip may have a maximum
bandwidth of 900 Kbps, for instance. If a DSL connection has a maximum
throughput of 500 Kbps, the VBR clip may stall.
Broadcasting VBR Clips
If you broadcast variable bit rate (VBR) video, your outgoing RealProducer
bandwidth as well as your viewers’ network connections should be able to
handle the maximum bandwidth requirement for your selected audience.
Note, however, that when you broadcast a VBR stream, bandwidth spikes
occur for each viewer at the same time. When broadcasting VBR, therefore,
your network needs to handle higher cumulative spikes than when you stream
prerecorded clips.
Tip: Multicast delivery, which is available on some intranets,
helps to overcome bandwidth spikes by delivering one stream
to all viewers, rather than a separate stream to each viewer. For
more information, refer to the multicasting chapter of Helix
Server Administration Guide.
VBR Maximum Bit Rate
The value of the Max Bitrate field caps the bandwidth that the VBR clip can
consume. This determines the highest value that the streaming bit rate can
reach. The maximum rate may occur during specific passages, such as highaction sequences, to improve video clarity.
79
Relationship to Average Bit Rate
Through most of a VBR video, the second-by-second bandwidth use is close to
the video’s average bit rate value. For example, a VBR clip may average 450
Kilobits of data per second. However, if the VBR audience defines a maximum
bit rate of 900 Kbps, the stream can, if necessary, consume up to 900 Kilobits
of data a second.
Tip: As you encode VBR clips for download, you can consider
the average bit rate as a guide to quality and file size. For
example, a 450 Kbps VBR download will generally have lower
quality and a smaller file size than a 750 Kbps VBR download.
For More Information: See “Video Average Bit Rate” on page 70.
Maximum Bit Rate Value
The maximum bit rate is typically 50 to 100 percent higher than the video’s
average bit rate. Although you can set the maximum bit rate value higher or
lower, a higher setting is unlikely to result in significantly greater quality. You
can lower the setting if you want to reduce the bandwidth spikes on your
network, however.
Tip: Lowering the maximum rate below 50 percent decreases
the benefits of VBR encoding. The closer the maximum rate
approaches the average rate, the more the clip behaves like a
CBR clip.
VBR Target Quality
The Target Quality setting gears the encoding process to achieve a certain level
of visual quality. With a quality of 100 percent, for example, RealProducer
attempts to reproduce the visual quality of the input nearly perfectly. A lower
quality, such as 90 or 80 percent, allows for more visual imperfections but
results in a smaller clip that uses less bandwidth.
Note: A quality setting does not guarantee perfectly faithful
reproduction of the input. It merely attempts to achieve the
quality level within the input constraints, such as the video
dimensions, frame rate, and bit rate.
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Relationship to Average Bit Rate
Because encoding for quality can vary the average bit rate greatly, the average
bit rate setting is ignored. That is, the average bit rate and quality settings are
mutually exclusive, and you can define only one of the values.
Quality-Based Encoding Example
If you set a maximum bit rate of 900 Kbps and a quality of 100 percent, for
example, the average bit rate may turn out to be close to 900 Kbps. At a lower
quality target, such as 80 percent, the average bit rate will probably be lower.
The actual, average bit rate depends greatly on content, though, and will vary
for each clip.
Streaming Quality-Based VBR Clips
Because their average bit rate can vary greatly, quality-based VBR clips are
better suited for downloading than streaming. However, you can stream a
quality-encoded stream as long as your network has the capacity to provide to
each user the bandwidth indicated by the maximum bandwidth target.
Typically, each stream will use less bandwidth than this.
Note: You can compute the average bandwidth of a clip by
dividing the file size in Kilobits by the number of seconds in
the timeline. For a live broadcast, though, it is impossible to
know the average bandwidth of a quality-encoded stream in
advance.
Tip: By editing an VBR audience file, you can vary the
relationships between bit rate and quality. You can also define
two additional variations of VBR encoding. For details refer to
RealProducer Command Line and Job File Reference.
Maximum Video Buffering (Preroll)
A video’s preroll sets the number of seconds of stream data that the media
player must receive before it starts to play the stream. You can modify the
preroll by changing the Max Video Buffer setting.
use: Sets the number of seconds the video buffers before starting.
restrictions: None.
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Tip: This startup latency does not affect how quickly a
downloaded clip begins to play. Increasing the preroll, however,
can improve the visual quality in download clips that begin
with fast-action sequences.
Maximum Key Frame Interval
Using the Max Key Frame Interval setting, you can change the video codec’s
value for the maximum time between key frames. The default value is at least
one key frame every 5 seconds.
medium: All video
use: Sets the maximum time in seconds between each key frame.
restrictions: Poor quality if set too low (1 to 2 seconds, for example).
Tip: Under most circumstances, you should not change the
default value. If you decide to modify the key frame rate, test
the output in a streaming environment to determine if the
change produces the desired results.
What is a Key Frame?
Compressed video encodes full frame data only for certain frames, called key
frames. A frame following a key frame encodes information that describes how
that frame varies from the preceding frame. The beginning of a new scene
typically requires a key frame. A fast-action video typically requires more key
frames than a slowly changing video.
Advantages of Lowering the Maximum Key Frame Interval
Lowering the maximum key frame interval can provide certain benefits:
• Reduces
distortion when streaming in a lossy environment. Distortion
results when a frame packet is lost. Using more frequent key frames helps
to shorten the stretch of video that may be distorted.
• Improves
timeline.
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a media player’s ability to seek to specific points in the video
Costs of Lowering the Maximum Key Frame Time
Because key frames encode more data than other frames, lowering the
maximum time between key frames either increases the clip’s file size or lowers
the clip’s image quality. You gain more resilience against data loss, but lose
overall compression efficiency.
Startup Latency Reduction During Broadcasts
A large key frame interval can cause a high stream acquisition latency during
live broadcasts. This latency is the time required for the media player to render
the stream after it begins to receive the broadcast data. If the media player
joins the broadcast just after the broadcast server streams a key frame, the
player may have to wait up to five seconds until the next key frame is available.
If Helix Server version 11 or later broadcasts the stream, however, it reduces
startup latency automatically by buffering each new key frame. This allows it
to send key frame data immediately to each media player as it acquires a
broadcast stream.
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PART
Part III:
BROADCASTING
This section covers broadcasting, explaining basic issues and
showing how to create server destinations.
III
CHAPTER
Chapter 9:
BROADCAST FEATURES
9
This chapter introduces you to the types of broadcasts, explains
broadcast options, and covers advanced broadcast features.
For More Information: When you are ready to set up a broadcast,
Chapter 10 explains how to define server destinations.
Live Broadcasting
In a live broadcast, RealProducer takes live input from a capture card as
described in “Capture Input” on page 29, encodes it in a streaming format,
and sends the stream to a broadcast server for replication and distribution to
media players.
Live Broadcasting
Tip: During a broadcast, you can encode the output as a file
destination. This saves the broadcast as an archived, ondemand clip. The section “Output File Destination” on page
55 explains how to do this.
Note: RealProducer can deliver a live broadcast only from live
input. To broadcast a file, encode the file in the appropriate
format using RealProducer. Then stream the file using the
Helix Server SLTA utility. For details, refer to Helix Server
Administration Guide.
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Broadcast Trial Runs
When you broadcast live content, you don’t get a second chance. It’s good
practice to perform a trial run to ensure that the broadcast results are
acceptable. During the trial run, do the following:
• Request
the stream from the broadcast server. When the media player
connects, check that the stream begins to play within a reasonable time.
• Confirm
that the stream rendered by the media player provides an
acceptable frame rate and visual quality.
• Monitor
RealProducer to check if it is using too much CPU.
Automatic Frame Rate Reduction
If RealProducer must reduce the processor load, it reduces the encoded frame
rate for the broadcast stream. If this happens, you can do one or more of the
following:
• Move
RealProducer to a faster machine.
• If
encoding multiple outputs, reduce the number of outputs. (See
“Outputs List” on page 49.)
• If
encoding multi-rate outputs, reduce the number of audiences encoded
for each output. (See “Encoding Settings” on page 50.)
• Use
an older video codec, such as RealVideo 8 instead of RealVideo 10.
(See “Video Codec” on page 70.)
• Lower
the streaming bit rate for one or more audiences. (See “Video
Average Bit Rate” on page 70.)
• Reduce
the video frame size. (See “Frame Size” on page 72.)
Types of Broadcasts
RealProducer provides several broadcast methods. Each method requires that
you define a different type of server destination:
• Push Broadcasting—RealProducer
delivers the broadcast stream to the
designated server as soon as encoding begins. The following broadcasting
modes are available:
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• Helix
Push Broadcast
• Helix
Advanced Push Broadcast
CHAPTER 9: Broadcast Features
• Helix
Multicast Push Broadcast
• Pull Broadcasting—After
encoding starts, RealProducer waits for each
broadcast server to request the stream. One broadcast method is available:
• Helix
Pull Broadcast
Helix Push Broadcast
A Helix Push broadcast requires little configuration on Helix Server. It
provides reliable delivery of the broadcast stream to one or more destinations.
server setup: Requires only a user name and password defined within the
Helix Server authentication database.
bandwidth: Each server destination receives a separate data stream. Each
server maintains a separate accounting connection.
feedback: Feedback statistics are sent in the accounting connection and
displayed in the Monitoring tab.
reconnection: Dropped streams are automatically re-established using the
accounting connection.
For More Information: The section “Helix Push Destination” on
page 105 explains how you set up this type of broadcast in
RealProducer.
Helix Push Broadcast Connection Steps
The following figure illustrates the interaction between RealProducer, Helix
Server, and a media player in a Helix Push broadcast.
Helix Push Broadcast
➤
Sequence of actions in a Helix Push broadcast:
1. RealProducer establishes its monitoring connection with Helix Server.
Using this connection, RealProducer sends a user name and password
that authenticates its access attempt.
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2. After Helix Server authenticates the broadcast, it informs RealProducer
how to make the broadcast connection, telling it which server ports to use,
for example.
3. RealProducer establishes the broadcast stream connection to Helix Server.
It begins to send the encoded packets whether or not any media players
have requested the broadcast yet.
4. A viewer typically requests the broadcast by clicking a link in a Web page.
This launches the viewer’s media player, which requests a broadcast
stream from Helix Server.
5. Helix Server streams the broadcast data to the media player.
URL for a Helix Push Broadcast
For a Helix Push broadcast that the viewer accesses by clicking a link in a Web
page, the URL looks like the following:
http://helixserver.example.com/ramgen/broadcast/news/live.rm
• The /ramgen/
mount point launches the media player when the viewer
clicks the link in a Web page.
• The /broadcast/
mount point is the default broadcast mount point. If
redundant encoders are used, the mount point is /redundant/ .
For More Information: See “Encoder Redundancy” on page 97.
•A
virtual path such as news/ is optional. It is included in the URL only if
RealProducer specifies this path along with the stream name.
For More Information: See “Virtual Paths” on page 106.
Note: Confer with the Helix Server administrator about the
actual URL to use. URLs can vary from the standard format for
many reasons.
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Helix Advanced Push Broadcast
Helix Advanced Push is similar to Helix Push broadcasting, but is more
efficient with bandwidth, making it a better choice when broadcasting to
multiple servers.
server setup: Requires that each Helix Server be configured as a broadcast
receiver.
bandwidth: Each server destination receives a separate data stream. There
are no accounting channels.
feedback: No feedback from the broadcast server.
reconnection: A server can re-establish a lost connection through metadata
that is encoded into the data stream periodically.
For More Information: The section “Helix Advanced Push
Destination” on page 110 explains how to set up this type of
broadcast in RealProducer.
Helix Advanced Push Broadcast Steps
The following figure shows the interaction between RealProducer, Helix
Server, and a media player in a Helix Advanced Push broadcast.
Helix Advanced Push Broadcast
➤
Sequence of actions in a Helix Advanced Push broadcast:
1. As soon as it starts encoding the broadcast stream, RealProducer sends
the stream packets to Helix Server. The password required by the Helix
Server receiver is encoded into the data stream.
2. A viewer typically requests the broadcast by clicking a link in a Web page.
This launches the viewer’s media player, which requests a broadcast
stream from Helix Server.
3. Helix Server delivers the broadcast data to the media player.
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URL for a Helix Advanced Push Broadcast
For a Helix Advanced Push broadcast that the viewer accesses by clicking a link
in a Web page, the URL looks like the following:
• The /ramgen/
• The /broadcast/
•A
many reasons.
Helix Multicast Push Broadcast
Helix Multicast Push is similar to Helix Advanced Push, except that the
transport is UDP multicast. This type of broadcast allows you to deliver a
single stream to multiple, multicast-enabled Helix Servers.
server setup: Requires that RealProducer, Helix Servers, and network
equipment such as routers be multicast-enabled.
bandwidth: Each server destination receives the same multicast stream.
There are no accounting channels between servers and
RealProducer.
feedback: No feedback from the broadcast servers.
reconnection: A server can re-establish a lost connection through metadata
that is encoded into the data stream periodically.
For More Information: The section “Helix Multicast Push
Destination” on page 114 explains how to set up this type of
broadcast.
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Multicast Push Illustration
The following figure illustrates multicasting. Because each server receives the
same stream, multicasting allows you to broadcast to any number of server
destinations without increasing the outgoing bandwidth from RealProducer.
Helix Multicast Push
Note: Multicasting may not be possible if RealProducer or any
of the Helix Servers needs to communicate to another
broadcast component across the Internet.
Tip: Multicast broadcasting can also be used for broadcasting
across a one-way satellite network where two-way connections
are not possible.
URL for a Helix Multicast Push Broadcast
For a Helix Multicast Push broadcast that the viewer accesses by clicking a link
in a Web page, the URL looks like the following:
• The /ramgen/
• The /broadcast/
•A
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many reasons.
Helix Pull Broadcast
In pull broadcasting, RealProducer begins to generate broadcast packets as
soon as you start the encoding process. However, it does not deliver the
broadcast stream until Helix Server requests the stream.
server setup: Requires that Helix Server be configured as a pull-enabled
receiver.
bandwidth: Each server receives a separate stream that it requests when
needed and drops when no longer in use.
feedback: No feedback statistics sent by the servers.
reconnection: Each server can automatically re-establish a stream that it has
dropped.
For More Information: The section “Helix Pull Destination” on
page 118 explains how to set up a pull broadcast.
Helix Pull Broadcast Steps
The following figure illustrates the interaction between RealProducer, Helix
Server, and a media player in a pull broadcast.
Helix Pull Broadcasting
➤
Sequence of actions in a Helix Pull broadcast:
1. RealProducer begins encoding the stream, but the output is not
immediately sent to Helix Server.
2. The first audience member requests the broadcast, typically by clicking a
link in a Web page. This launches the media player, which requests the
broadcast stream from Helix Server.
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3. Helix Server requests the broadcast stream from RealProducer, sending it
information about the server address and ports to use. Once the
connection is established, Helix Server sends keep-alive requests as long as
viewers are receiving the broadcast.
4. RealProducer sends the broadcast stream to Helix Server, terminating the
stream when it receives no more keep-alive messages.
5. Helix Server streams the broadcast to media players.
Example of Pull Broadcasting
An example of a pull broadcast is an online radio station that continuously
encodes input. The stream is delivered to a specific Helix Server only if a
listener requests the stream from that server. If all listeners on the server stop
the broadcast, Helix Server drops the stream, re-requesting it only if new
listeners request the broadcast.
Stream Acquisition Latency
Because a Helix Pull broadcast does not begin until the first media player
requests the broadcast, the first viewer may experience a longer than normal
delay as Helix Server contacts RealProducer to acquire the broadcast stream.
After the server acquires the stream, however, subsequent viewers experience
no additional delay.
Outgoing Bandwidth
When you use pull splitting, you do not have control over how many Helix
Servers pull the stream. Any server that knows the RealProducer address,
stream name, and access password can request the stream. You therefore have
less control over your outgoing RealProducer bandwidth than you do with
push splitting, in which you define exactly which servers receive the stream.
Note: Each Helix Server that requests the broadcast receives a
separate stream. Multicasting is not available with pull
splitting.
URL for a Pull Broadcast
The URL to a Helix Pull broadcast is longer than a URL to a push broadcast
because it includes information about both the Helix Server receiver and the
RealProducer transmitter.
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The following example shows the general format for a basic Helix Pull
broadcast that the viewer accesses by clicking a link in a Web page. For
convenience, the example is displayed on two lines. The first line gives the
receiver information. The second line supplies the transmitter parameters:
http://receiver.example.com/ramgen/broadcast/pull/ 
producer.example.com:3031/news/live.rm
• The /ramgen/
• The /broadcast/
mount point is the default mount point used by Helix
Server for a broadcast. Following the broadcast mount point is a path that
indicates pull splitting is used, as in /pull/ . The Helix Server receiver
defines this path.
• The
link’s transmitter portion lists the RealProducer IP address or host
name, along with its listen port, as in producer.example.com:3031.
•A
Server Broadcast Mode
The broadcast method you use with RealProducer affects only the delivery of
the broadcast stream to the server. The broadcast server, in turn, determines
the method for broadcasting the live stream to media players. For example,
RealProducer may deliver the stream to the server in pull mode while the
server broadcasts in push mode.
Options that you choose for the encoder-to-server broadcast stream do not
necessarily affect streams that the server delivers to other servers or to media
players. For example, you might choose a 20 percent forward error correction
(FEC) rate in a push broadcast. This FEC rate affects only the encoder-toserver stream. A Helix Server transmitter can forward (split) the stream to a
Helix Server receiver using a different FEC rate. Streams delivered to media
players include no FEC packets.
For More Information: Refer to the chapter on transmitters and
receivers in Helix Server Administration Guide for information
about replicating streams from one server to another.
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Broadcast Transports
When you run a push broadcast other than a multicast, you specify whether to
use TCP or UDP for the broadcast stream sent to the server. The server,
however, determines whether TCP or UDP is used in the broadcast streams
replicated to media players.
UDP
The UDP transport is preferred because of its lower network overhead.
However, UDP connections do not receive notice if broadcast packets are lost.
A server can generally notify RealProducer if it requires data to be resent,
however.
A firewall between RealProducer and the server may block UDP packets. The
best solution is to configure the firewall to allow UDP packets through the
ports that RealProducer and the server use for the broadcast data stream.
TCP
The TCP transport establishes a two-way connection between RealProducer
and the server. If a broadcast packet is lost, the network itself requests the
packet to be resent. This makes TCP a highly reliable method for broadcasting
on networks prone to data loss. TCP is also likely to pass through firewalls
that you cannot configure to accept UDP communications.
TCP incurs a higher network overhead, however. A server generally does not
need all broadcast packets to keep the stream flowing. Packets re-requested by
the TCP transport may arrive at Helix Server too late to be useful. Hence,
using TCP involves network-related overhead that may not benefit the
broadcast.
Encoder Redundancy
When broadcasting in Helix Push or Helix Advanced Push mode, you can
provide encoder redundancy by using two or more RealProducers to encode
the same live event.
When you start each broadcast stream, you specify the same stream name, but
add a unique, numbered delimiter, such as .1 or .2 . When the RealProducers
connect to Helix Server, they form a queue based on connection order.
Consider this example:
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live.rm.2 connects first
live.rm.3 connects second
live.rm.1 connects third
Under normal circumstances all viewers receive the stream live.rm , and have no
knowledge of which RealProducer encoded the stream. In the preceding
example, live.rm originates as live.rm.2 .
If the RealProducer delivering live.rm.2 fails, the media players connect to the
next live.rm stream in the queue, which is live.rm.3 . If live.rm.2 returns, it goes
to the bottom of the queue. A subsequent failure of live.rm.3 causes media
players to connect to live.rm.1, and so on.
RealProducer Redundancy
Note: Encoder redundancy changes the broadcast URL. The
Helix Server administrator may also require the use of a
different delimiter, such as a tilde (~), in the stream identifier.
Refer to the unicasting chapter of Helix Server Administration
Guide.
Tip: To provide optimal redundancy, each encoder should be as
independent as possible. For example, use multiple video
cameras connected to separate RealProducer computers that
use different power supplies and network connections.
Forward Error Correction
When forward error correction (FEC) is used, RealProducer adds error
correction packets to the broadcast stream. If packets containing broadcast
data are lost, Helix Server can often reconstruct the data using the error
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correction information. You can include forward error correction with
broadcasts that use the UDP transport. The setting is ignored for any
broadcast that uses TCP.
Tip: Forward error correction is most useful when sending a
broadcast stream over a lossy network such as the Internet. If
your RealProducer and Helix Server are on the same local area
network, you may not need to use any error correction.
Error Correction Percentage
The greater the FEC percentage, the higher the packet loss protection and the
greater the bandwidth needed for the stream. A standard value of 20 percent
means that one in five packets is for error correction. The stream also uses 20
percent more bandwidth than if error correction was turned off.
Note: Using FEC increases the bandwidth only for the stream
between RealProducer and Helix Server. It does not affect the
bandwidth of the broadcast streams delivered to media players
by Helix Server.
Redundant Stream Protection
You can turn the FEC percentage up to 100%, effectively creating a redundant
stream that provides maximum protection against packet loss. This doubles
the outgoing bandwidth between RealProducer and Helix Server, however.
When you use full stream redundancy, you can set an offset in seconds
between each packet and its redundant packet. This reduces the chance that
both packets will be lost. For example, an offset value of 2 means that after it
transmits a certain packet to Helix Server, RealProducer waits two seconds
before transmitting the redundant packet.
Note: Packet redundancy does not protect against the failure of
the encoding process. Use encoder redundancy to protect
against RealProducer going offline during a broadcast. See
“Encoder Redundancy” on page 97.
FEC Rates and Receiver Buffering
When you use FEC, the Helix Server administrator may need to increase the
buffering of the broadcast stream. If an FEC packet arrives after the server
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broadcasts the portion of the stream that the FEC packet corrects, the packet
is useless.
Full Stream Redundancy Buffering Levels
If you use full stream redundancy, Helix Server must buffer the stream at least
as long as the redundant packet offset value. For example, if RealProducer
transmits redundant stream packets five seconds after the initial stream
packets, the Helix Server receiver needs to buffer the stream for a minimum of
five seconds.
Partial Stream Redundancy Buffering Levels
When you use partial stream redundancy, broadcasting low-bandwidth video
streams with an error correction rate lower than 20 percent may require
raising the receiver buffering time.
For More Information: The chapter on transmitters and receivers
in Helix Server Administration Guide explains how to set the
receiver buffering based on the transmitter FEC rate.
Archiving
When you broadcast a live event, you can write the stream to a clip for
archiving or for streaming on-demand. You can archive a RealMedia clip
through RealProducer, Helix Server, or both. A primary consideration is disk
space. Writing a long broadcast to a clip can consume considerable disk space
depending on the broadcast bandwidth.
Tip: The server may have more available space than your
RealProducer computer. As well, creating the archive on the
server eliminates the need to upload the archive clip later if you
want to stream it on demand.
RealProducer Archiving
To archive a broadcast on RealProducer, you define a clip destination along
with the server destination. RealProducer automatically creates a new clip if
the existing archive reaches the operating system limit (typically 2 or 4
Gigabytes).
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Tip: If you run a RealMedia broadcast from the command line
or manually create a job file for the broadcast, you can specify a
different file-rolling limit based on broadcast time or file size.
For More Information: The section “Output File Destination” on
page 55 explains how to create an archive clip.
Helix Server Archiving
The Helix Server administrator can turn on archiving for RealMedia
broadcasts. Like RealProducer, Helix Server can create multiple archive files
based on the broadcast time (such as a new file every 15 minutes), or file size
(20 Megabytes per file, for example). The administrator can also set up
selective archiving rules that archive only certain broadcast streams based on
the presence of a virtual path in the stream name.
For More Information: See the unicasting chapter of Helix Server
Administration Guide for information about archiving.
Version 6 IP Addresses
RealProducer supports DNS names, version 4 IP addresses (IPv4), and version
6 IP addresses (IPv6) for delivering a broadcast stream to a server. Note the
following about using IPv6 addresses:
• RealProducer
supports full IPv6 syntax, such as the following:
1080:0:0:0:8:800:200C:417A
It also supports the use of a double colon (“::”) to compress leading or
trailing fields containing only zeroes, as in the following:
1080::8:800:200C:417A
• RealProducer
will not broadcast to a reserved multicast address. However,
it will multicast to permanent or nonpermanent addresses, which always
begin with FF, as in FF15:0:0:0:0:0:0:101.
Tip: Whenever possible, use a domain name instead of an IPv6
address.
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CHAPTER
Chapter 10:
SERVER DESTINATIONS
10
Server destinations deliver a live stream to a server. The server then
broadcasts the stream to media players. The procedure for delivering
a live stream depends on the type of broadcast server that
RealProducer uses.
Note: You must create an output as explained in Chapter 5
before you can assign a server destination to an output.
For More Information: Refer to Chapter 9 for background about
broadcasting options.
Server Destinations
You create a server destination for a selected output in the Output Servers
section of the Output tab. Each server destination defines a set of broadcast
parameters, such as the server IP address and password.
Output Servers Settings
Output Servers Buttons
The buttons in the Output Servers section allow you to configure the server
destinations:
Add a destination server template to the selected output.
Edit the broadcast settings for the selected server template.
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Save the settings to a new server template.
Delete the selected server destination from the output. (This
does not delete the template.)
Server Destination Templates
Click the Add button— —to add a server destination to the output
highlighted in the Outputs List. The pop-up dialog displays the server
templates stored in the RealProducer servers subdirectory.
Add Server Destinations
In the Templates of Server Type drop-down, choose one of the following based
on the type of broadcast you want to run:
• All Helix Broadcast Types —All
• Helix Push —See
broadcast types for Helix Server.
“Helix Push Destination” on page 105.
• Helix Advanced Push —See
“Helix Advanced Push Destination” on page 110.
• Helix Multicast Push —See
“Helix Multicast Push Destination” on page 114.
• Helix Pull —See
“Helix Pull Destination” on page 118.
If you have defined a customized server destination template that you want to
use, click the template name. Otherwise, select the Default template. Then click
Add to Job.
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CHAPTER 10: Server Destinations
Tip: Using the preferences, you can select a server destination
that is used automatically whenever you create an output. See
Template Filtering by Name
You can filter the templates shown in the server destinations pop-up by typing
a string in the Where name matches field. Only destination names that contain
the string then display. Text matching is not case-sensitive.
Multiple Server Destinations
You can deliver each broadcast stream to one or more broadcast servers. In the
server destinations pop-up, use Ctrl+click to select multiple, discrete server
destinations. Use Shift+click to select a range of destinations. You can also add
destinations one at a time by clicking the Add button repeatedly.
Note: Each push server destination you add increases the
outgoing bandwidth requirements, unless you use
multicasting.
Server Template Creation
After you set up your server destinations, you can save modifications for
future jobs. Once you finish customizing a server destination, highlight the
server destination name and click the Save As button— .
A standard save dialog allows you to choose a new template name. Or you can
select an existing template to overwrite that template. Templates are saved in
servers subdirectory of the RealProducer installation directory using the file
extension .rpsd .
Tip: Use a descriptive name that clearly identifies the purpose
of the template.
Helix Push Destination
A Helix Push broadcast is a simple method for delivering a live stream to Helix
Server. RealProducer delivers the broadcast stream to the destination Helix
Server as soon as encoding begins.
Note: If you are not familiar with this broadcast method, refer
to the section “Helix Push Broadcast” on page 89 for
background information.
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Helix Push Basic Settings
A Helix Push destination defines the stream name and Helix Server address,
along with a name and password that provides access to the server.
Basic Settings for the Helix Push Server Destination
Name
Enter a description for this server destination in the Name field. For example,
the name might identify the broadcast method and indicate the Helix Server
that receives the stream. This name is for your reference only. It does not affect
the broadcast.
Server Type
In the Server Type drop-down, select Helix Push .
Stream Name
In the Stream Name field, enter a name for the broadcast stream. This name
should use the appropriate extension for the output type. It appears in links
to the broadcast URL.
Note: The stream name can include uppercase or lowercase
letters, numbers, an underscore (_), and a hyphen (-). Spaces
are not allowed.
Virtual Paths
If you want to archive or split the broadcast on Helix Server, the server
administrator first sets up a virtual path such as news/ that defines archiving
or splitting rules. You then precede the stream name with this path, as in
news/live.rm , to utilize the rule.
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For More Information: See the chapter on transmitters and
receivers in Helix Server Administration Guide for details about
using virtual paths.
Encoder Redundancy
If you are using encoder redundancy, include the appropriate stream delimiter
and a unique number for this encoder. For example:
live.rm.2
Server Address
For Server Address, enter the version 4 IP address, version 6 IP address, or DNS
name of the Helix Server that receives the broadcast stream. The following are
examples of each type of address:
• 207.188.7.176
• FEDC:BA98:7654:3210:FEDC:BA98:7654:3210
• helixserver.example.com .
Server HTTP Port
For Server HTTP Port, specify the HTTP port value on Helix Server. The
default value is port 80, which is the default HTTP port on Helix Server.
RealProducer uses this port to contact Helix Server once encoding has begun.
Data Ports
When RealProducer contacts Helix Server on its HTTP port, the two negotiate
which ports to use for the broadcast data. The broadcast requires at least two
data ports on Helix Server whether the transport is TCP or UDP. Possible
ports are in the range 50001 to 50050 unless the Helix Server administrator
changes the default range.
Username and Password
In the Username and Password fields, enter a valid encoder user name and
password. These values are defined in the Helix Server authentication
database under the SecureRBSEncoder realm. The broadcast connection fails if
either value is incorrect.
For More Information: For details, refer to the unicasting and
authentication chapters of Helix Server Administration Guide.
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Save Password in Job
Click Save Password in Job to store the password in the current job file.
Warning! The password is saved as plain text in the server
template and any job file that later uses this server destination.
Be sure to maintain appropriate security on these files.
Transport
Under Transport, click the radio button for UDP or TCP to select the transport
to use for the broadcast stream.
Note: The monitoring connection of a Helix Push broadcast
always uses TCP whether the data transport stream is UDP or
TCP.
For More Information: See “Broadcast Transports” on page 97.
Helix Push Advanced Settings
Click the Advanced Settings button to display additional options for the Helix
Push server destination. You should not modify the advanced settings values
unless you have a specific reason to do so.
Advanced Settings for the Helix Push Server Destination
Reconnect Interval
The Reconnect Interval value defines the number of seconds that RealProducer
waits before attempting to reconnect to Helix Server. The interval period
begins once the operating system terminates the TCP accounting connection
because it has received no response from Helix Server. The default value is 30 .
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Statistics Update Interval
The statistics update interval determines how frequently Helix Server sends
statistics reports to RealProducer during a Helix Push broadcast. The default
value is 30 seconds.
Listen Address
RealProducer uses the IP address or domain name listed in the Listen Address
field to listen for resend requests from Helix Server. Use the drop-down to
select the version 4 or version 6 IP address that you want to use on the
RealProducer machine. You can also enter a domain name or IP address
manually.
Tip: Using an IP address of the RealProducer machine may not
work when you broadcast through a network address
translation (NAT) firewall. In this case, set the listen address to
0.0.0.0 instead.
Accept Resend Requests
If Helix Server loses broadcast packets and cannot reconstruct them using
forward error correction, it can request that RealProducer resend the packets
from its stream buffer. To enable RealProducer to respond to these requests,
check the Accept Resend Requests from Server box.
Tip: It’s generally OK to accept resend requests. However,
because these requests increase network overhead slightly, you
may want to turn the resend feature off to keep tight control
over bandwidth.
The Percent Error Correction field sets the percentage of stream bandwidth
dedicated to forward error correction packets if the transport is UDP. A value
of 20, for example, increases outgoing bandwidth 20 percent by making every
fifth packet an FEC packet.
If you set the error correction percentage in the range of 51 to 100 , you set up a
redundant stream. In this case, the Redundant Packets Offset field defines how
many seconds separate an original packet from its redundant packet.
For More Information: The section “Forward Error Correction”
on page 98 provides background about FEC features.
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Helix Advanced Push Destination
In a Helix Advanced Push broadcast, RealProducer acts as a transmitter for
delivering a live stream. The Helix Server that receives the broadcast stream is
set up as a receiver. This robust broadcast method requires coordinated setup
on both ends.
to the section “Helix Advanced Push Broadcast” on page 91 for
in Helix Server Administration Guide explains how to set up Helix
Server as a receiver.
Helix Advanced Push Basic Settings
A Helix Advanced Push destination sets the stream name and provides the
information necessary to connect to the Helix Server receiver.
Basic Settings for the Helix Advanced Push Server Destination
Name
the name might identify the broadcast method and indicate the intended
receiver. This name is for your reference only. It does not affect the broadcast.
Server Type
In the Server Type drop-down, select Helix Advanced Push .
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Stream Name
are not allowed.
Virtual Paths
Encoder Redundancy
If you are using encoder redundancy, include the appropriate stream delimiter
and a unique number for this encoder. For example:
live.rm.2
Server Address
For Server Address, enter the version 4 IP address, version 6 IP address, or DNS
name of the Helix Server receiver used for the broadcast. The following are
examples of each type of address:
• 207.188.7.176
• FEDC:BA98:7654:3210:FEDC:BA98:7654:3210
Note: The Helix Server receiver definition must specify the
RealProducer IP address as its transmitter source. See the
chapter on transmitters and receivers in Helix Server
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Server Port
For Server Port, specify a Helix Server port used by the receiver for incoming
data. Receiver ports are typically 30001 to 30020, but the Helix Server
administrator may change this range. The default server port that
RealProducer uses for data transmission is 30001.
Password
In the Password field, enter a valid receiver password. This password is stored
as part of the Helix Server receiver configuration. Note the following:
• The
password does not need to be defined in the Helix Server
authentication database.
•A
user name is not needed with this type of broadcast.
• Optionally,
the receiver can require no authentication. In this case, leave
Password blank.
Warning! Non-authenticated transmission should be used only
if RealProducer and Helix Server are on the same local network
and a firewall blocks attempts by outside encoders to reach
Helix Server.
Transport
Under Transport, click the radio button for UDP or TCP to select the transport
to use for the broadcast stream.
Note: The Helix Server receiver configuration must specify the
same transport. See the chapter on transmitters and receivers
in Helix Server Administration Guide.
For More Information: See “Broadcast Transports” on page 97.
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Helix Advanced Push Advanced Settings
Advanced Push server destination. You should not modify the advanced
settings values unless you have a specific reason to do so.
Advanced Settings for the Helix Advanced Push Server Destination
Reconnect Interval
The Reconnect Interval setting defines the interval in seconds at which
RealProducer encodes metadata values into the broadcast stream. These
values allow Helix Server to reconnect to a dropped broadcast stream. The
default is 30 seconds.
Listen Address
RealProducer uses the IP address or domain name listed in the Listen Address
field to listen for resend requests from Helix Server. Use the drop-down to
select the version 4 or version 6 IP address that you want to use on the
RealProducer machine. You can also enter a domain name or IP address
manually.
Tip: Using an IP address of the RealProducer machine may not
work when you broadcast through a network address
translation (NAT) firewall. In this case, set the listen address to
0.0.0.0 instead.
Accept Resend Requests
If Helix Server loses broadcast packets and cannot reconstruct them using
forward error correction, it can request RealProducer to resend the packets
from its stream buffer. To enable RealProducer to respond to these requests,
check the Accept Resend Requests from Server box.
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Tip: It’s generally OK to accept resend requests. However,
because these requests increase network overhead slightly, you
may want to turn the resend feature off to keep tight control
over bandwidth.
Note: The Helix Server receiver configuration can turn off the
feature for making resend requests. In this case, the
RealProducer setting has no effect because the server will never
make these requests.
dedicated to forward error correction packets if the transport is UDP. A value
of 20, for example, increases outgoing bandwidth 20 percent by making every
fifth packet an FEC packet.
Helix Multicast Push Destination
In a multicast, RealProducer acts as a transmitter that delivers a live stream.
Multiple, multicast-enabled Helix Servers function as receivers. This
configuration requires a multicast-enabled network as well as coordinated
setup on both ends.
to the section “Helix Multicast Push Broadcast” on page 92 for
in Helix Server Administration Guide explains how to set up each
Helix Server receiver.
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Helix Multicast Push Basic Settings
The following figure illustrates the basic settings for a Helix Multicast Push
destination.
Basic Settings for the Helix Multicast Push Server Destination
Tip: Unlike Helix Push and Helix Advanced Push broadcasts,
which require a separate server destination for each broadcast
server, a Helix Multicast Push broadcast requires just one
server destination. Any number of multicast-enabled servers
can then receive the stream by listening to the defined
multicast address and port.
Name
the name might identify the broadcast as a multicast to a known set of
receivers. This name is for your reference only. It does not affect the broadcast.
Server Type
In the Server Type drop-down, select Helix Multicast Push .
Stream Name
are not allowed.
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Virtual Paths
Multicast Address
For Multicast Address, enter a version IP version 4 or 6 multicast address:
• IPv4
multicast addresses are in the range 224.0.0.0 to 239.255.255.255 .
• IPv6
multicast addresses have the prefix ff00::/8 .
RealProducer IP address as its transmitter source. It must also
define udp/multicast as the transport. See the chapter on
transmitters and receivers in Helix Server Administration Guide.
Multicast Port
For Multicast Port, specify a Helix Server port used by the receiver for
incoming data. Receiver ports are typically 30001 to 30020, but the Helix
Server administrator may change this range. The default Helix Server port
that RealProducer uses for data transmission is 30001.
Note: Ensure that any firewalls between RealProducer and the
Helix Servers allow UDP data sent to Helix Server on the
chosen port.
Password
• The
•A
• Optionally,
Password blank.
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if RealProducer and all Helix Servers are on the same local
network and a firewall blocks attempts by outside encoders to
reach any of the Helix Servers.
Transport
For a multicast, the Transport field is not selectable because multicasts always
use the udp/multicast transport.
Helix Multicast Push Advanced Settings
Multicast Push server destination. You should not modify the advanced
settings values unless you have a specific reason to do so.
Advanced Settings for the Helix Multicast Push Server Destination
Multicast TTL
For Multicast TTL, specify a packet time-to-live of 0 to 255 . As a multicast data
packet passes through a multicast-enabled router, its time-to-live decreases by
1. When the value reaches 0, the router discards the data packet. The larger the
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value, the greater the distance each packet can travel. The following table
summarizes possible values.
Time to Live (TTL) Values
TTL Value
Packet Range
0
local host
1
local network (subnet)
16
intranet
32
site
64
region
128
continent
255
world
Tip: The default value of 16 typically keeps multicast packets
within an internal network.
Reconnect Interval
The Reconnect Interval setting defines the interval in seconds at which
RealProducer encodes metadata values into the broadcast stream. These
values allow Helix Servers to reconnect to a dropped broadcast stream. The
default is 30 seconds.
dedicated to forward error correction packets. A value of 20, for example,
increases outgoing bandwidth 20 percent by making every fifth packet an FEC
packet.
Helix Pull Destination
In pull broadcasting, RealProducer begins to generate broadcast packets as
soon as you start the encoding process. However, it does not deliver the
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broadcast stream until a Helix Server requests the stream. In a Helix Pull
broadcast, RealProducer acts as a transmitter and Helix Server functions as a
pull-enabled receiver.
to the section “Helix Pull Broadcast” on page 94 for
in Helix Server Administration Guide explains how to set up the
server as a pull-enabled receiver.
Helix Pull Basic Settings
The following figure illustrates the basic settings for a Helix Pull destination.
Basic Settings for the Helix Pull Server Destination
Tip: Unlike Helix Push and Helix Advanced Push broadcasts,
which require a separate server destination for each broadcast
server, a Helix Pull broadcast requires just one server
destination. Any number of servers can then pull the stream by
contacting RealProducer on its listen port.
Name
Enter a description for this server destination in the Name field. With an
online radio station, for example, the name might identify the type of music
being broadcast. This name is for your reference only. It does not affect the
broadcast.
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Server Type
In the Server Type drop-down, select Helix Pull .
Stream Name
are not allowed.
Virtual Paths
Encoder Address
For Encoder Address, select the version 4 or version 6 IP address used by
RealProducer to listen for pull requests. If your computer has just one IP
address, that address is selected by default in the drop-down list.The following
are examples of each type of address:
• 207.188.7.176
• FEDC:BA98:7654:3210:FEDC:BA98:7654:3210
RealProducer IP address as its transmitter source. See the
chapter on transmitters and receivers in Helix Server
Encoder Listen Port
For Encoder Listen Port, specify the RealProducer port used to listen for stream
pull requests. You can use any available port up to 65535. The default is 3031.
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Note: The Helix Server receiver must be configured to contact
RealProducer on this port. See the chapter on transmitters and
receivers in Helix Server Administration Guide.
Data Ports
RealProducer does not transmit broadcast data on the listen port. Rather,
both RealProducer and Helix Server define a range of ports for stream data.
They negotiate which ports to use during the initial pull request. The default
ports on both are 30001 to 30020.
Tip: Ensure that any firewalls between RealProducer and Helix
Server allow UDP data sent to Helix Server on the ports in the
defined range.
Password
• The
•A
• Optionally,
Password blank.
if RealProducer and Helix Server are on the same local network
and a firewall blocks attempts by outside encoders to reach
Helix Server.
For More Information: For receiver configuration details, refer to
the chapter on transmitters and receivers in Helix Server
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Transport
For a pull broadcast, the Transport field is not selectable because pull
broadcasts use the transport defined by the Helix Server receiver.
Helix Pull Advanced Settings
Pull server destination. You should not modify the advanced settings values
unless you have a specific reason to do so.
Advanced Settings for the Helix Pull Server Destination
Note: In a Helix Pull broadcast, the Helix Server receiver
configuration sets up most of the advanced broadcast features,
such as forward error correction parameters.
Keep Alive Timeout
The Keep Alive Timeout value specifies the number of seconds that
RealProducer waits before it stops transmitting broadcast packets after it
receives no more keep-alive messages from Helix Server. This conserves
bandwidth by dropping a stream no longer in use. The Helix Server that drops
the stream can re-establish it if necessary, however. The default timeout value
is 30 seconds.
Tip: You can raise the value if previous pull broadcasts have
timed out while viewers were still receiving the broadcast.
RealNetworks does not recommend that you lower the value.
Note: A keep-alive timeout stops only the transmission of the
packets. It does not stop the encoding of the packets. You must
stop the encoder manually.
122
PART
Part IV:
MONITORING
This section explains how to monitor an encoding session to
check for errors and view encoding statistics.
IV
CHAPTER
Chapter 11:
11
JOB MONITORING
This chapter explains how to start an encoding job and describes
how to monitor a job in progress.
Monitoring Tab
Click the Monitoring tab to display the controls that help you to monitor
encoding jobs.
Monitoring Tab
The controls on the Monitoring tab allow you to do the following:
• Start
and stop an encoding job (see “Starting a Job” on page 126).
• Preview
video output (see “Preview Section” on page 126).
• Monitor
audio levels (see “Audio Meters” on page 127).
125
• View
session errors (see “Session Logging” on page 129).
Note: The settings advisor may also display above the
Monitoring tab if RealProducer detects problems with the
encoding settings. The section “Settings Advisor” on page 130
explains this feature.
Starting a Job
Once you have set up the inputs and outputs for a job and there are no critical
error messages noted by the settings advisor, you can start the encoding
process. Do this by selecting Control>Start Job, pressing Ctrl+j, or clicking the
Start Job button— —on the toolbar.
When you encode a clip or set a duration on captured input (see “Input
Duration” on page 29), encoding stops automatically when the job is
complete. To stop the encoding process manually, select Control>Stop Job or
click the Stop Job button on the toolbar.
Note: If there are multiple outputs or destinations, stopping
the job halts the encoding process for all outputs and
destinations. You cannot stop the encoding for one output or
for one destination (such as a clip) while continuing it for
another destination (such as a broadcast server).
Preview Section
The top section of the Monitoring tab contains two preview monitors. When
the encoding job includes video, the input source video plays in the left-hand
monitor, which shows the effects of all prefilters that have been applied. The
encoded output displays in the right-hand monitor.
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CHAPTER 11: Job Monitoring
Input and Output Preview Monitors
The control in the upper-left corner of the Preview section allows you to show
or hide the monitors.
Monitors Hidden—Click to expand the Preview section.
Monitors Displayed—Click to hide the section.
Tip: Hiding the monitors can speed the encoding process by
eliminating the need for RealProducer to display the video
onscreen. This is useful during live broadcasts in which you
want to conserve as much processing power as possible.
Multiple Output Display
When you encode multiple outputs, use the Output drop-down to select which
output to monitor in the right-hand monitor window. If the output encodes
more than one audience, select the audience by encoding speed using the
Bitrate drop-down.
Audio Meters
As you encode the output, you can monitor the audio levels for both the input
audio and the encoded output audio.
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Audio Meter
By monitoring the audio meters, you can ensure that the audio levels are in
the optimal dynamic range:
• green—Normal
• red—Audio
dynamic range.
is close to being overmodulated.
For More Information: The section “Audio Level” on page 38
explains how to use the audio gain prefilter to boost or cut the
input’s audio level.
Clipped Audio
If audio registers above the possible dynamic range, the clipping indicator
above the audio meter lights up. To eliminate the distortion, you may need to
modify the setting of the audio level prefilter or adjust the settings in your
audio mixing hardware or software.
For example, the sound capture card may have its mixer levels set too high. In
this case, adjust the analog gains leading to your sound card input so that the
input audio meter on RealProducer never rises to the 0 dB level. If needed,
modify audio gain through an external mixer board if the sound card’s audio
mixer does not provide adequate control.
Tip: External mixing may lead to sound levels that are too low
on average. In this case, you can use the audio level prefilter to
bring the signal back up to acceptable levels. This is safe to do
because the prefilter will not introduce clipping.
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CHAPTER 11: Job Monitoring
Session Logging
RealProducer records messages about encoding tasks as they occur. This
informs you about RealProducer performance, such as its CPU use. After a job
has run, you can view the producer.log log file in the main installation
directory to find encoding errors messages. You can also use the session log
viewer to monitor encoding information as the job runs.
For More Information: The preferences file (producer.pref ) sets
the log file location and features. It also determines which
types of messages display in the log viewer. For details, refer to
“Log File Preferences” on page 135.
Session Log Viewer
The session log viewer appears at the bottom of the Monitoring tab. It provides
a real-time view of log messages as RealProducer generates them. The control
in the upper-left corner of the Session Logging section allows you to show or
hide the previews.
Session Logging Hidden—Click to display Session Logging.
Session Logging Displayed—Click to hide the section.
Tip: Click Clear Log to remove existing messages from the
screen. This does not delete the messages from the log file,
however.
Note: Watching the log viewer is useful when you encode a live
broadcast. The messages can alert you to problems such as
excess CPU consumption and lowered frame rates.
Logging Types
You can organize the log messages by type by clicking the Type column header.
All messages are one of the following types:
error
Error messages indicate significant problems that have occurred in
the encoding process. They typically cause the job to fail.
warning
Warning messages indicate serious issues that occurred but did not
cause the encoding job to fail.
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informational Informational messages provide important information about the
encoding operation.
diagnostic
Diagnostic messages convey non-critical messages about the
encoding operation.
Tip: The preferences file (producer.pref ) determines which
message types are logged. By default, diagnostic messages are
not recorded. See “Log File Preferences” on page 135.
For More Information: For information about changing the
logging settings, refer to “Log File Preferences” on page 135.
Settings Advisor
RealProducer displays the settings advisor at the top of the Monitor, Input, and
Output tabs to inform you that it has detected problems with the selected
encoding settings. All messages displayed by the settings advisor are flagged to
indicate the severity of the message.
Error—Job cannot run using the current settings. You must correct the
problem before the job will start.
Warning—Selected settings do not comply with standards. The job will run
but the encoded content may not play on some media players.
Information—Selected settings do not comply with best practices. However,
the encoded content is likely to play on most media players.
Note: Click the question mark icon (
) to the right of the
message to display detailed information about the problem.
Tip: Click Settings Advisor on the toolbar to toggle the display
of the settings advisor.
130
PART
Part V:
APPENDIXES
The following appendixes contain useful reference information.
V
APPENDIX
Appendix A:
A
PREFERENCES
The RealProducer preferences affect the operation of both the
graphical application and the command-line application.
Preferences File
RealProducer records application preferences in the file producer.pref , located
in the main installation directory. This text file specifies values such as the
temporary directory, encoding defaults, and tolerance levels for audio and
video warnings. Using the graphical application, you can edit the preferences
by selecting the File>Preferences menu entry.
Note: You must restart RealProducer to put preference changes
into effect.
File Location Preferences
Choose Edit>Preferences and click the File Locations tab to set the directory
paths for certain files used by RealProducer.
File Location Preferences
133
Template Directories
The Audience and Server fields specify the locations of the templates that hold
encoding and broadcast parameters, respectively. You typically do not need to
change the template locations unless you want to move template files to a
common location shared by multiple installations of RealProducer.
By default, these templates are stored in the audiences and servers directories of
the main installation directory. To change the locations, click the Open
buttons— —and navigate to the appropriate directories on your file system.
Note: You must copy the existing template files to the new
template directories manually. Restart RealProducer to put the
changes into effect.
For More Information: See “Audience Templates” on page 51 and
“Server Destination Templates” on page 104.
Temporary Directory
RealProducer uses the temporary directory to write temporary data when
encoding on-demand clips. It deletes the temporary files after it has fully
encoded the output clip.
Output File Directory
Click the Same Location as Destination File radio button to write temporary
data to the same directory that will hold the output file. This is recommended
only if you write output files to the local disk on the RealProducer machine.
The encoding process may slow down if you write temporary data to a
networked, shared directory.
Specific Directory
Click the Other radio button and then the Open button— —to select a
specific directory to use as the temporary directory. To use the same directory
specified by the Windows TEMP variable, enter the following in the field:
%TEMP%
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APPENDIX A: Preferences
Log File Preferences
Click Edit>Preferences and choose the File Logging tab to set the RealProducer
logging preferences. These preferences affect how both the command-line
application and the graphical application log encoding events.
Tip: Logging is enabled automatically. You can disable it by
editing the producer.pref file directly. For more information, see
the preferences appendix of RealProducer Command Line and Job
File Reference.
Logging Preferences
Log File Location
The standard log file is a text file named producer.log that resides in the main
installation directory. Click the Open button— —to navigate to a different
directory. You can change the file name directly in the preferences field after
you select the new directory.
Logging Settings
The options in the Logging Settings section allow you to set the basic logging
choices.
Message Format
For Message Format, choose one of the following:
135
• Detailed —Record
full information, such as the message category,
functional area, time, and message number.
• short —Record
only the job name and message.
Message Severity
In the Message Severity section, you can select up to four logging categories.
Choose any combination of the following:
Errors
Error messages indicate significant problems that have occurred in
the encoding process. These problems typically caused the encoding
process to fail. The problem must be corrected for encoding to
continue.
Warnings
Warning messages indicate possible problems in the encoding
process. For example, RealProducer logs a warning if its audio
watchdog detects that stereo input channels are out of balance.
Warning messages also alert you to encoding settings that may make
the stream unplayable on certain media players.
Information
Informational messages provide important but non-critical
information about the encoding operation. They also alert you to
encoding settings that do not follow best practices.
Diagnostic
Diagnostic messages convey non-critical messages about
RealProducer operation. Because an encoding operation may
generate many diagnostic messages, the log file can grow rapidly if
you include the Diagnostic category.
Functional Area
Each message is part of a functional area. For example, messages concerning
audio codec operation fall under the Audio Codec area. Each functional area
may include errors, warnings, informational messages, and diagnostic
messages. Under Functional Area, select the functional area messages that you
want to log in the log file.
Logging Functional Areas
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Functional Area
Events Logged
ActiveX
Events specific to the ActiveX control used by Windows-based
programs to encode media using RealProducer.
Audio Codec
Events involving an audio codec used for the job. For details
about setting audio codecs, refer to “Audio Encoding
Settings” on page 63.
Logging Functional Areas
Functional Area
Events Logged
Audio Prefilters
Events concerning the use of an audio prefilter. See “Audio
and Video Preprocessing” on page 37.
Broadcast
Events that occur when transmitting a live stream to Helix
Server. For an introduction to broadcast issues, refer to “Live
Broadcasting” on page 87.
Capture
Events around the capture of input media. See “Capture
Input” on page 29 for capture setup instructions.
Command Line
Events that occur when running the command-line
application. The document RealProducer Command Line and Job
File Reference explains the use of this application.
File Output
Events involved with writing encoded media streams to a file.
The section “Output File Destination” on page 55 explains
how to set up a file as the output.
File Reader
Events related to reading an audio or video file.
GUI
Events related to the use of the graphical application.
Job File
Events related to the use of a job file.
Postfilters
Events related to post-filters added by the RealProducer SDK.
Remote Agent
Events related to the remote agent.
SDK Configuration
Events concerning the set up of jobs.
SDK Encoding
Events related to encoding activities.
SDK Core
Events specific to the core SDK.
SDK Generic Filter
General events about prefilters or postfilters.
Statistics
Events that affect statistics processing.
Video Codec
Events related to the video codec.
Video Pre-filters
Events concerning the use of a video prefilter.
Video Rendering
Events related to video preview.
Log File Rolling
The log rolling feature creates a new log file when the current log file reaches a
certain size or time limit. Using log rolling is recommended if you encode
many streams or capture diagnostic messages to the log file. To set up log file
rolling, click the Enable Log File Rolling box. Then choose the criterion for
rolling the log file:
137
• Log
Size
To create a new log file when the current file reaches a certain size, select
the Roll File Every radio button. Then choose a file size in Megabytes.
• Log
Time
To create a new log file at a regular interval, click the Roll at End of Every
radio button. Then select Hour, Day, Week , or Month .
Tip: The active log file is always the name you define in the Log
File Location field. Archived log files have an integer value
appended to their file extensions, such as producer.log1 and
producer.log2 . Lower numbers indicate earlier archives.
Output Preferences
Click Edit>Preferences and choose the Output Settings tab to set default
encoding settings such as the audience template used. This is useful if you
repeatedly encode the same clip or broadcast, such as a program updated every
hour. When you create a new job, RealProducer automatically fills in the
appropriate fields of the Output tab with the default values.
Output Preferences
138
Note: The default settings are used only with the graphical
application. They do not apply to jobs processed by the
command-line application.
Encoding Defaults
For Encoding Settings, you can pick one or more audiences used to encode the
output stream, whether a clip or a live broadcast. Click the Open button— —
to display the templates dialog. Next, select one or more audiences.
For More Information: See “Audience Templates” on page 51.
Output Directory and File Name Defaults
The Output Filename field defines a standard file name and output directory
for encoded clips. If you want to define a directory where all encoded files are
written, click the Open button— —and select the directory. Alternatively, you
can define file path variables.
File Name and Path Variables
For the output file name and path, you can use any of the following variables.
RealProducer then substitutes the appropriate value when it runs the job.
%JobName% Name of the current job file.
%InputFilename% The input file name without the path or file extension.
%InputFileDir% The input file's absolute directory path without the file name or
extension.
%OutputName% The output name. See “Output Name” on page 50.
%OutputType% An output type designation: rm .
%OutputTypeExt% The default file extension for the output type: rm .
File Name and Path Examples
The following are examples of setting the default output file path and name
using variables.
Input File Directory and Output File Name
The following values writes the output file to the same directory that holds
the input file:
%InputFileDir%\%OutputName%.%OutputTypeExt%
139
The file name is the output name selected on the Output tab (see “Output
Name” on page 50) along with the appropriate file extension.
Standard Directory with Input File Name
The next example writes the output the C:\media directory on each job:
C:\media\%JobName%.%OutputTypeExt%
The output file uses the name of the input job file along with the appropriate
output file extension.
Output Server Defaults
For Output Servers, you can select a server destination template used by
default. This is useful if you always deliver broadcasts of this media type using
the same server. Click the Open button— —and select one of the destination
templates.
For More Information: See “Server Destination Templates” on
page 104.
Metadata Defaults
The Metadata fields allow you to define a standard set of metadata values for
each output. You can define some or all values. For example, you might set
only a default copyright date and author string for each stream.
For More Information: Refer to “Metadata Titles and Values” on
page 58.
Signal Detection Preferences
The preferences (File>Preferences) on the AV Signal Detection tab affect audio
and video tests run during the encoding process. These tests write warnings to
the log file if RealProducer detects problems with the incoming audio or video
stream. This is useful with live input to indicate problems with capture cards,
cabling, cameras, microphones, and so on.
140
Signal Detection Preferences
Tip: Typically, you can leave these values set to their defaults,
changing them only if erroneous error messages are written to
the log file.
Audio Watchdog Tests
Click the Enable Audio Watchdogs box to run the audio watchdogs for all
encoding jobs. You can then adjust the tolerances, if necessary, for each audio
test.
Silence
The Silence test warns if the audio signal does not rise above a certain decibel
setting for a certain period. You can set the decibel level and the required
duration.
Silence Level
In digital audio signals, 0 dB represents the maximum audio level. Each
decrease of 6 decibels indicates a reduction in the audio level by half. The
default value of -60 represents a complete loss of the audio signal.
Tip: Select a level in decibels high enough to distinguish
between background noise and true silence. In clean audio
feeds, noise levels are low, and you can set this value low. For
noisier feeds, such as those originating from analog sound
141
cards, a low value may incorrectly identify noise as an active
audio signal.
Silence Duration
You can specify a period in seconds over which this condition must persist to
be considered an error. This screens out normal audio lapses, such as when
cutting to a commercial break. The default is 10 seconds.
Channel Imbalance
A channel imbalance occurs when one of the stereo channels is six decibels
higher or lower than the other channel. The audio watchdog issues a warning
if this condition persists for a certain period. The default is 10 seconds.
Clipping
Clipping occurs when the audio peak reaches 0 decibels (maximum level). At
this point, distortion typically occurs. This audio watchdog warns that the
audio is being clipped heavily, moderately, or lightly. You can specify a period
in seconds over which this condition must persist. The default is 10 seconds.
Out of Phase
This warning is logged if the left and right channels of a stereo signal are out
of phase. You can specify a period in seconds over which this condition must
persist. The default is 10 seconds.
Video Watchdog Tests
Click the Enable Video Watchdogs box to run the video watchdogs for all
encoding jobs. You can then adjust the tolerances, if necessary, for the video
watchdog tests.
No Signal (Single Color Image)
The No Signal test detects that the video image is a single, unchanging color.
This typically indicates the lack of a video signal.
Note: This test does not identify color bars in the video stream.
No Signal Complexity Value
For the No Signal test, you can set a complexity value used to identify if a video
frame is a solid color. The complexity value ranges from 0 (solid color) to 100
(white noise). The default is 5 .
142
Tip: Lower the value if warnings about missing signals are
consistently reported for video streams that are OK. Raise the
value if missing signal conditions are underreported.
No Signal Duration
You can also set a duration that defines how long the No Signal condition can
occur before a warning is logged. The default value is 10 seconds.
Noisy Signal (White Noise)
The Noisy Signal test detects white noise. This condition occurs when the
video receiver cannot find a signal and reads background noise.
Noisy Signal Complexity Value
The Noisy Signal test has a complexity value used to identify if a video frame is
white noise. The complexity value ranges from 0 (solid color) to 100 (white
noise). The default is 95 .
Tip: Raise the value if white noise warnings are consistently
reported for video streams that are OK. Lower the value if
white noise conditions are underreported.
Noisy Signal Duration
You can also set a duration that defines how long the Noisy Signal condition
can occur before a warning is logged. The default value is 10 seconds.
Frozen Signal (Color Bars)
The Frozen Signal test warns that the video image has not changed. This
condition can occur if the image is frozen or the video output displays color
bars.
Frozen Signal Complexity Value
The Frozen Signal test sets a factor used to gauge if video frames are changing.
The default is 0.5 .
Tip: Lower the value if frozen signal warnings are consistently
reported for video streams that are OK. Raise the value if
frozen signals are underreported.
Frozen Signal Duration
You can also set a duration that defines how long the Frozen Signal condition
can occur before a warning is issued. The default value is 10 seconds.
143
Message Suppression
Audio and video watchdog messages can rapidly fill the log file if the
problems persist. To cut down on the number of messages, enter a value in
minutes in the Suppress duplicated messages for... field. A value of 5 , for
example, means that each warning is reported every five minutes as long as the
condition persists.
Frame Analysis Period
The value for the last field on this preferences tab determines how frequently
the video watchdog tests run. Limiting the tests to once every 30 seconds, for
example, helps to minimize CPU usage.
144
APPENDIX
Appendix B:
AUDIENCE TEMPLATES
B
Information in this appendix will help you to choose which
audiences to use when encoding a clip or broadcast.
Predefined Audience Templates
An audience template defines a range of parameters used to encode a clip or
broadcast. For example, it defines the audio and video codec, along with the
streaming bandwidth. RealProducer provides a number of predefined
templates stored as files (file extension .rpad ) in its audiences subdirectory.
Templates Included with RealProducer
Most predefined video templates are available in three versions: RealVideo,
H.263, and H.264. Audio-only templates are available for RealAudio, AAC,
AAC+, and MP3. Each version uses the codecs and features appropriate for
that output type.
Note: H.264, H.263, AAC, AAC+, and MP3 templates do not
function with RealProducer.
Audio-Only Templates
The audio-only templates are for CBR audio output. They do not define any
video settings:
• 16k
Voice
• 32k
Music
• 64k
Music
• 96k
Music
Tip: You can also use a video template to encode an audio-only
output. RealProducer simply ignores the video settings.
145
Video Templates (CBR)
Constant bit rate video templates define settings for streaming video and
audio:
• 28k
Video
• 56k
Video
• 65k
Video
• 80k
Video
• 100k
Video
• 150k
Video
• 300k
Video
• 750k
Video
• 1.5M
Video
Tip: You can add multiple CBR audiences to the same output
to create a rate-shifting RealMedia stream.
VBR Quality Template
The variable bit rate template is designed for downloadable video clips in the
RealMedia format:
• 90%
VBR Quality Video
Note: A VBR clip can encode only one audience.
Customized Templates
RealProducer offers many more encoding choices than those available using
the predefined templates. In many cases, you’ll want to create your audience
templates that cover your specific encoding needs. To do this, start with the
predefined template that is closest to your desired output. Then edit the
template using RealProducer. When it has the new settings you want, save the
template under a new name.
16k Voice
The 16 Kb audio audiences target low-bandwidth, audio-only streaming of
voice content (no music). There are three predefined audiences:
146
APPENDIX B: Audience Templates
• 16k R5 Voice.rpad —3GPP
Release 5, 3GPP Release 6, or MPEG-4
• 16k R6 Voice.rpad —3GPP
Release 6 or MPEG-4
• 16k RA Voice.rpad —RealAudio
The following table lists the encoding settings for these audiences.
16k Audio Audience Settings
Setting
16k R5
16k R6
16k RA
Audio bandwidth
12.2 Kbps
15.85 Kbps
16 Kbps
Audio codec
AMR-NB
AMR-WB
RealAudio Voice
Audio channels
1
1
1
Rate control type
CBR
CBR
CBR
28k Video
The 28 Kb video audiences target low-bandwidth video streaming. There are
three predefined audiences:
• 28k H.263.rpad —3GPP
Release 6 or MPEG-4
• 28k RV.rpad —RealVideo
28k Video Audience Settings
Setting
28k H.263
28k H.264
28k RV
Video average bandwidth
20 Kbps
20 Kbps
20 Kbps
Audio bandwidth
8 Kbps
8 Kbps
6 Kbps
Audio codec
AAC-LC
AAC+
RealAudio
Audio channels
1
1
1
Video codec
H.263
H.264
RealVideo 10
Video profile
0
Baseline
NA
Video level
auto
auto
NA
Maximum video frame rate (fps)
7.5
7.5
7.5
Preroll (buffering time)
1 second
1 second
4 seconds
Quality
20
20
20
147
Setting
28k H.263
28k H.264
28k RV
Encoding complexity
high
high
high
Rate control type
CBR
CBR
CBR
32k Music
music. There are four predefined audiences:
• 32k MP3 Music.rpad —MP3
• 32k AAC Music.rpad —3GPP
• 32k AAC+ Music.rpad —3GPP
Release 6 or MPEG-4
• 32k RA Music.rpad —RealAudio
Setting
32k MP3
32k AAC
32k AAC+
32k RA
Audio bandwidth
32 Kbps
32 Kbps
32 Kbps
32 Kbps
Audio codec
MP3
AAC-LC
AAC+
RealAudio
Audio channels
2
2
2
2
Rate control type
CBR
CBR
CBR
CBR
56k Video
Release 6 or MPEG-4
148
Setting
56k H.263
56k H.264
56k RV
44 Kbps
44 Kbps
44 Kbps
Audio bandwidth
12 Kbps
12 Kbps
12 Kbps
Audio codec
AAC-LC
AAC+
RealAudio
Audio channels
1
1
2
Video codec
H.263
H.264
RealVideo 10
Video profile
0
Baseline
NA
Video level
auto
auto
NA
7.5
7.5
7.5
1 second
1 second
4 seconds
Quality
30
30
30
Encoding complexity
high
high
high
Rate control type
CBR
CBR
CBR
64k Music
Release 6 or MPEG-4
Setting
64k MP3
64k AAC
64k AAC+
64k RA
Audio bandwidth
64 Kbps
64 Kbps
64 Kbps
64 Kbps
Audio codec
MP3
AAC-LC
AAC+
RealAudio
Audio channels
2
2
2
2
Rate control type
CBR
CBR
CBR
CBR
149
65k Video
Release 6 or MPEG-4
Setting
65k H.263
65k H.264
65k RV
53 Kbps
53 Kbps
53 Kbps
Audio bandwidth
12 Kbps
12 Kbps
12 Kbps
Audio codec
AAC-LC
AAC+
RealAudio
Audio channels
1
1
2
Video codec
H.263
H.264
RealVideo 10
Video profile
0
Baseline
NA
Video level
auto
auto
NA
10
10
10
1 second
1 second
4 seconds
Quality
35
35
35
Encoding complexity
high
high
high
Rate control type
CBR
CBR
CBR
80k Video
The 80 Kb video audiences target medium-bandwidth video streaming. There
are three predefined audiences:
Release 6 or MPEG-4
150
Setting
80k H.263
80k H.264
80k RV
64 Kbps
64 Kbps
64 Kbps
Audio bandwidth
16 Kbps
16 Kbps
16 Kbps
Audio codec
AAC-LC
AAC+
RealAudio
Audio channels
1
1
2
Video codec
H.263
H.264
RealVideo 10
Video profile
0
Baseline
NA
Video level
auto
auto
NA
15
15
15
1 second
1 second
4 seconds
Quality
40
40
40
Encoding complexity
high
high
high
Rate control type
CBR
CBR
CBR
96k Music
The 96 Kb audio audiences target high-bandwidth, audio-only streaming of
Release 6 or MPEG-4
Setting
96k MP3
96k AAC
96k AAC+
96k RA
Audio bandwidth
96 Kbps
96 Kbps
96 Kbps
96 Kbps
Audio codec
MP3
AAC-LC
AAC+
RealAudio
Audio channels
2
2
2
2
Rate control type
CBR
CBR
CBR
CBR
151
100k Video
The 100 Kb video audiences target high-bandwidth video streaming. There are
• 100k H.263.rpad —3GPP
• 100k H.264.rpad —3GPP
Release 6 or MPEG-4
Setting
100k H.263
100k H.264
100k RV
80 Kbps
80 Kbps
80 Kbps
Audio bandwidth
20 Kbps
20 Kbps
20 Kbps
Audio codec
AAC-LC
AAC+
RealAudio
Audio channels
1
2
2
Video codec
H.263
H.264
RealVideo 10
Video profile
0
Baseline
NA
Video level
auto
auto
NA
15
15
15
1 second
1 second
4 seconds
Quality
45
45
45
Encoding complexity
high
high
high
Rate control type
CBR
CBR
CBR
150k Video
• 150k H.263.rpad —3GPP
• 150k H.264.rpad —3GPP
Release 6 or MPEG-4
152
Setting
150k H.263
150k H.264
150k RV
122 Kbps
122 Kbps
118 Kbps
Audio bandwidth
28 Kbps
28 Kbps
32 Kbps
Audio codec
AAC-LC
AAC+
RealAudio
Audio channels
2
2
2
Video codec
H.263
H.264
RealVideo 10
Video profile
0
Baseline
NA
Video level
auto
auto
NA
15
15
15
1 second
1 second
4 seconds
Quality
50
50
50
Encoding complexity
high
high
high
Rate control type
CBR
CBR
CBR
300k Video
• 300k H.263.rpad —3GPP
• 300k H.264.rpad —3GPP
Release 6 or MPEG-4
Setting
300k H.263
300k H.264
300k RV
244 Kbps
252 Kbps
256 Kbps
Audio bandwidth
56 Kbps
48 Kbps
44 Kbps
Audio codec
AAC-LC
AAC+
RealAudio
Audio channels
2
2
2
Video codec
H.263
H.264
RealVideo 10
Video profile
0
Baseline
NA
153
Setting
300k H.263
300k H.264
300k RV
Video level
auto
auto
NA
30
30
30
1 second
1 second
4 seconds
Quality
60
60
60
Encoding complexity
high
high
high
Rate control type
CBR
CBR
CBR
750k Video
The 750 Kb video audience targets medium-quality video downloading. There
are two predefined audiences:
• 750k H.264.rpad —3GPP
Release 6 or MPEG-4
154
Setting
750k H.264
750k RV
Maximum bandwidth
686 Kbps
686 Kbps
686 Kbps
686 Kbps
Audio bandwidth
48 Kbps
64 Kbps
Audio codec
AAC+
RealAudio
Audio channels
2
2
Video codec
H.264
RealVideo 10
Video profile
Baseline
NA
Video level
auto
NA
30
30
1 second
4 seconds
Quality
70
70
Encoding complexity
high
high
Rate control type
CBR
VBRBitrate
1.5M Video
The 1.5 Mb video audience targets high-quality video downloading. There are
two predefined audiences:
• 1.5M H.264.rpad —3GPP
Release 6 or MPEG-4
• 1.5M RV.rpad —RealVideo
1.5M Video Audience Settings
Setting
1.5M H.264
1.5M RV
Maximum bandwidth
1.404 Mbps
1.404 Mbps
1.404 Mbps
1.404 Mbps
Audio bandwidth
96 Kbps
96 Kbps
Audio codec
AAC+
RealAudio
Audio channels
2
2
Video codec
H.264
RealVideo 10
Video profile
Baseline
NA
Video level
auto
NA
30
30
1 second
4 seconds
Quality
80
80
Encoding complexity
high
high
Rate control type
CBR
VBRBitrate
90% VBR Quality Video
The 90% VBR Quality video audience targets high-quality video downloading.
It attempts to preserve near-perfect video quality within the constraints of
maximum bandwidth, frame size, and video content. There is one predefined
audience:
• 90% VBR Quality RV.rpad —RealVideo
155
The following table lists the encoding settings for this audience.
1.5M Video Audience Settings
156
Setting
90% RV
Maximum bandwidth
2 Mbps
2 Mbps
Audio bandwidth
96 Kbps
Audio codec
RealAudio
Audio channels
2
Video codec
RealVideo 10
Video profile
NA
Video level
NA
30
4 seconds
Quality
90
Encoding complexity
high
Rate control type
VBRQuality
APPENDIX
Appendix C:
AUDIO AND VIDEO TIPS
C
This appendix provides tips for capturing and editing audio and
video input. This information will help you to encode higher-quality
output streams.
Audio Capture
A streaming clip reflects the quality of its audio source. Any quality problems
within the source will affect the streaming clip as well. Because you cannot
edit a broadcast, live Webcasting introduces several issues beyond those
involved with delivering on-demand clips. This section will help you capture
high-quality audio source files, or set up your sound equipment to deliver
good broadcasts.
Source Media
If you plan to stream existing material, start with the best source possible. Use
the cleanest recording with the least amount of unwanted noise. CDs, DVDs,
and digital audio tapes (DATs) are good source media. Well-recorded analog
sources such as records, reel-to-reel tapes, and chrome (Type II) cassettes can
also sound good. Avoid consumer-grade recording media such as Type I
cassettes and VHS tapes.
Recording Equipment
Every piece of equipment in the audio chain—microphone, mixer, sound card,
and so on—affects sound quality. If you intend to provide professional-quality
audio content, invest in professional-quality audio equipment and software.
Lesser equipment can add hiss and distortion, degrading sound clarity.
157
Shielded Cables
It is important to use high-quality, shielded cables. Using unshielded cables
increases the likelihood of introducing line noise and radio frequency
interference into recordings. Keep audio cables physically separated from
power cords to minimize the introduction of noise. Also be sure to ground all
equipment properly.
Input Levels
Setting correct input levels is crucial. All audio equipment has a dynamic
range, the ratio between the loudest possible sound the equipment can
reproduce without distortion and its inherent “noise floor.” Also called
“clipping,” distortion of this type is audible as a high-frequency crackling
noise.
To get the best dynamic range, set the input level on each audio device in the
signal chain so that it uses its full range of available amplitude without
distortion during the program’s loudest sections. The signal chain typically
includes a microphone, a mixing desk, a compressor, and a sound card. For
each piece of equipment, set levels as close as possible to 0 decibels without
going over that level.
Check for signal distortion at each point in the signal chain. Perform several
test runs, and make sure that there are no peaks above maximum amplitude.
Adjust the levels on your sound card mixer so that the input approaches but
does not exceed the maximum. Be conservative, though. Levels might
suddenly increase if, for instance, an interviewee suddenly speaks loudly or a
crowd at a sports event roars.
Volume Levels for Live Broadcasts
When broadcasting live audio streams, it is useful to have a dynamics
compressor for gain compression (not data compression). This piece of audio
equipment automatically adjusts the volume level. By providing a consistent
volume level, it allows you to “set and forget” the input levels to RealProducer.
Sampling Rates
Try to capture sound with a sampling width of 16 bits. RealAudio codecs have
different sampling rates that produce the best sound, however. If your sound
card allows it, capture audio content at the optimum sampling rate for the
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APPENDIX C: Audio and Video Tips
codec you intend to use. RealProducer will convert the file to the optimum
rate if necessary, but this is recommended only for static files. For live
broadcasts, use a sound card that supports the optimum rate. This avoids the
overhead entailed in converting the rate while encoding sound in real time.
Tip: You do not need to capture stereo sound if you plan to use
a mono codec. However, many sound cards simply discard the
right input channel in mono mode. If you have a mixing desk,
pan all inputs to the center so that nothing is lost during the
conversion to mono.
Audio Optimization
If you are not broadcasting audio live, you typically start with digitized audio
source files in supported input formats, such as WAV. Although RealProducer
can adjust audio levels during encoding, you achieve the best quality for
editing files before encoding them.
To optimize audio files this, you need to be familiar with the features your
editing program offers. This section gives you some optimization tips you can
try with your editing software before encoding your clips with RealProducer.
Tip: Always keep copies of your audio source files. You cannot
convert encoded clips back to their original source formats.
DC Offset
DC offset is low-frequency, inaudible noise that results from equipment
grounding problems. If you don’t remove it, it can skew the results of
subsequent sound editing. Use your sound editor’s DC Offset function
immediately after recording a digital audio file.
Tip: If your editing program has this option, remove DC offset
during recording. This eliminates an editing step.
Normalization
Set sensible input levels when recording, and then use normalization to
maximize the levels after recording. Your streaming files sound best when
your digitized source has the highest possible gain without clipping. Digital
audio files that do not use their full amplitude range produce low-quality
159
streaming clips. If the amplitude range is too low, use your sound editor to
adjust the range and increase the amplitude.
Tip: Most sound editors have a Normalize function that
maximizes levels automatically. Because some systems have
trouble with files normalized to 100 percent, normalize to 95
percent of maximum, or to -0.5dB.
Dynamics Compression
Normalization maximizes the volume level of the audio file’s loudest sections.
Consequently, quiet sections may not encode as well. Dynamics compression
evens out input levels by attenuating (turning down) the input when it rises
above a specified threshold. Check your audio software for a Compression or
Dynamics feature. You can control attenuation by specifying a compression
ratio. This turns down the loudest sections, and you can readjust input levels
accordingly.
Tip: For multipurpose dynamics compression, set the
threshold to -10dB, the ratio to 4:1, and the attack and release
times to 100ms. Adjust the input level to get approximately
3dB of compression and an output level of about 0dB.
Equalization
Equalization (EQ) changes the tone of the incoming signal by “boosting”
(turning up) or “cutting” (turning down) certain frequencies. Using EQ, you
can emphasize certain frequencies and cut others that contain noise or
unwanted sound.
EQ can compensate for codecs that do not have flat frequency responses (that
is, codecs for which certain frequencies are not as loud after encoding). You
can therefore use EQ to make an encoded audio clip sound as close as possible
to the source recording.
Tip: For voice-only content, you can make the file more
intelligible by cutting frequencies below 100 Hz and carefully
boosting frequencies in the 1000 to 4000 Hz range.
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APPENDIX C: Audio and Video Tips
Video Recording
If you intend to shoot a new video rather than use existing video content, this
section provides tips for capturing high-quality input. Because video loses
image quality if it’s highly compressed, always start with the best video source
available.
For More Information: For pointers on recording audio, see
“Audio Capture” on page 157.
Video Staging
Consider the video’s final frame size before you shoot the first frame.
Streaming over a slow data connection requires a small video window, so you
need to frame important visual elements well. For recommended clip
dimensions, see “Frame Size” on page 72.
Scene Changes and Movement
The fewer things that change from frame to frame, the sharper the image will
appear in a low-bandwidth video. You can do the following to cut down on
unnecessary movement:
• Use
a mounted camera rather than hand-held one. This greatly reduces
the movement you inadvertently introduce into the scene when recording.
• Don’t
have a rapidly moving object fill the entire frame. But you don’t
want to pull the camera back too far either. You need to find a happy
medium between close-ups and panoramic shots.
Of course, you don’t want to eliminate all dynamic elements. When you do
include rapid movement, allow enough time for objects to resolve. Because of
low frame rates and high compression, objects coming to rest may appear
blurry at first. If you have a dialog box popping up on a computer screen, for
example, have the box remain stationary for a few seconds so that the image
resolves.
Colors and Lighting
Bright lighting at a constant exposure keeps the foreground detail crisp. Use
uniformly dark colors for backgrounds, and uniformly light colors (but not
whites) for clothing. Complex textures such as paisley and stripes degrade the
final image quality with unwanted visual effects.
161
Video Output
Video playback devices commonly have at least two common output types—
S-video and composite. Use S-video, as it produces better results.
Professional-grade devices typically have other, high-quality output modes
that can connect to a video capture card.
Color Depth
Always use 24-bit or 32-bit color. Lower color resolution results in poor clips.
Source Media Quality
Whether you shoot a video yourself or digitize existing material, start with
high-quality video media. The following are common video formats, listed in
order of descending quality:
1. HDV
2. Betacam SP, also known simply as Beta. This format is common among
video production professionals.
3. DV, miniDV, DVCam, or DVCPro.
4. Super-VHS (S-VHS) or HI-8mm.
5. VHS, 8mm.
162
INDEX
A
arch file name addition, 55
archiving broadcasts, 100
audience templates
1.5M Video, 155
100k Video, 152
150k Video, 152
16k Audio, 146
28k Video, 147
300k Video, 153
32k Audio, 148
56k Video, 148
64k Audio, 149
65k Video, 150
750k Video, 154
80k Video, 150
90% Quality Video, 155
96k Audio, 151
ocation, 134
predefined files, 145
audiences
adding to output, 51
customizing, 52
templates
deleting, 54
saving as, 53
audio
cables, 158
capture, 29
channels, 64
codec choice, 64
customization, 63
DC offset, 159
digitizing, 159
dynamics compression, 160
equipment quality, 157
filters, 37
frequency equalization, 160
gain, 38, 158
input formats, 11
input levels, 158
mixer, 30
monitoring levels, 127
muting, 38
normalization, 159
optimizing, 159
recording tips, 157
resampling while broadcasting, 68
sampling rates
choosing, 68
for codecs, 13
sampling width, 158
signal detection, 141
signal-to-noise ratio, 158
source media, 157
synchronizing with video, 39
vendor controls, 30
B
bandwidth
negotiation, 18
rate-shifting clips, 18
Betacam video, 162
black-level correction, 46
broadcasting
archive clip, 87
audio resampling, 68
audio volumes, 158
broadcast quality, 88
encoder redundancy, 97
forward error correction, 98
from a file, 87
IP version 6, 101
redundant stream protection, 99
TCP transport, 97
trial run, 88
163
UDP transport, 97
video startup latency, 83
see also Helix Push broadcast
see also Helix Multicast Push broadcast
see also Helix Advanced Push broadcast
see also Helix Pull broadcast
C
cable shielding, 158
channel imbalance detection, 142
clipping detection, 142
color bar detection, 143
D
de-interlace filter, 42
digital video formats, 162
DirectX requirements, 11
discrete multichannel audio
description, 66
encoding with stereo codecs, 67
sound system requirements, 67
supported number of channels, 67
dynamics compression, 160
F
file input, 27
film-to-video transfer, 42
firewall problems during broadcasts, 109,
113
forward error correction, 98
frame rates
when capturing video, 33
see also video
H
hardware requirements, 7
Helix Advanced Push broadcast
advantages of, 91
archiving, 111
broadcast steps, 91
metadata resend interval, 113
overview, 110
redundant encoders, 111
server
authentication, 112
destination, 110
ports used, 112
stream name, 111
164
URLs, 92
Helix Multicast Push broadcast
archiving, 116
metadata resend interval, 118
multicast address, 116
packet TTL, 117
server
authentication, 116
ports used, 116
stream name, 115
URLs, 93
Helix Pull broadcast
advantages of, 94
archiving, 120
broadcasting steps, 94
outgoing bandwidth, 95
overview, 118
server
authentication, 121
ports used, 120
stream acquisition latency, 95
stream name, 120
URLs, 95
Helix Push broadcast
archiving, 106
broadcast steps, 89
overview, 89
ports
data, 107
HTTP, 107
redundant encoders, 107
server
authentication, 107
destinations, 105
statistics update interval, 109
stream name, 106
URLs, 90
I
Input tab, 25
inputs
audio formats accepted, 11
file
selecting, 27
start and stop times, 33
live capture, 29
Index
audio controls, 30
audio mixer, 30
duration, 29
frame rate, 33
video dimensions, 32
source properties, 35
video formats accepted, 11
installation
Windows, 7
interlaced video, 42
inverse-telecine filter, 42
IP addresses
version 6, 101
J
job file
creating, 26
opening, 27
samples, 26
saving, 26
syntax, 26
upgrading, 27
jobs, 126
K
key frames, 82
L
log viewer, 129
logging
category, 136
disabling, 135
file name, 135
file rolling
enabling, 137
file size, 138
interval, 138
format, 135
functional areas, 136
message severity, 136
M
metadata, 57
Monitoring tab, 125
mono audio encoding, 64
multicasting
overview, 114
packet time to live (TTL), 117
multichannel audio
see discrete multichannel audio
see stereo surround
N
NAT firewall traversal, 109, 113
O
OpenDML, 28
output file, 55
Output tab, 47
outputs
defining, 49
monitoring, 127
P
packet time to live, 117
phase balance detection, 142
pixel aspect ratio, 45
preferences
audio signal detection, 140
file paths, 133
logging, 135
preference file, 133
video signal detection, 140
prefilters
audio gain, 38
audio synchronization, 39
de-interlace, 42
input cropping, 39
inverse-telecine, 42
noise, 43
resize, 44
Q
QuickTime input sources, 12
R
rate control
clip encoding requirements, 19
codec choice, 20
downshifting and upshifting, 19
encoding times, 18
multi-rate clips, 18
rate-shifting clips, 19
streaming rates, 20
rate shifting, 19
RealAudio
165
choosing, 64
codecs
discrete multichannel, 16
high response, 14
mono music, 15
stereo music, 15
stereo surround, 16
voice, 13
converting to other formats, 159
overview, 13
RealVideo
codecs
RealVideo 10, 17
RealVideo 8, 18
RealVideo 9, 17
compressed input, 11
converting to other formats, 11
file rolling, 57
frame rate mode, 76
overview, 17
.rmvb extension, 17
S
166
sampling rates
setting, 68
server destinations, 104
Helix Advanced Push broadcast, 110
Helix Multicast Push broadcast, 114
Helix Pull broadcast, 118
Helix Push broadcast, 105
saving as templates, 105
template location, 134
settings advisor, 130
shielded cables, 158
silence detection, 141
source properties, 35
stereo audio encoding, 64
stereo surround
encoding as standard stereo, 66
overview, 65, 66
sources for, 65
supported number of channels, 65
SureStream, see rate control
s-video, 162
T
tabs
input, 25
monitoring, 125
output, 47
XML, 26
TCP transport, 97
temporary directory, 134
two-pass encoding, 56
U
UDP transport, 97
V
variable bit rate encoding, 78
maximum bit rate, 79
quality, 80
VHS format, 162
video
advanced settings, 77
artifacts, 43
average bit rate, 70
capture, 29
disk space, 28
file size limit, 28
formats, 11
frame rates, 33
requirements, 28
codec selection, 70
cropping, 39
effect on broadcasts, 39
dimensions
desktop media, 75
portable devices, 72
resizing methods, 73
encoding complexity, 75
filters, 37
frame rates
factors that affect, 71
variable nature, 71
frame size
multi-rate streams, 21
setting, 72
input formats, 11
interlaced, 42
key frame maximum
benefits of lowering, 82
Index
costs of lowering, 83
overview, 82
lighting, 161
minimizing movement, 161
motion resolution, 161
noise reduction, 43
preroll setting, 81
recording tips, 161
resize quality, 73
resizing, 44
resizing output, 72
source formats, 162
staging shots, 161
s-video, 162
synchronizing with audio, 39
24-bit depth, 162
variable bit rate encoding, 78
Video for Windows, 11
video stream, 143
signal detection, 142
white noise detection, 143
volume for live broadcasts, 158
W
white noise detection, 143
Windows installation, 7
X
XML tab, 26
167
168

realproducer user`s guide

Transcription

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