Helix Universal Server and Proxy, Version 15

Release Notes

Helix Universal Server

Helix Universal Server Professional

Helix Proxy Server

15.1 General Release

8 October 2013

Helix Universal Server and Proxy, Version 15

Copyright © 2012 RealNetworks, Inc. This product may incorporate one or more of the following: U.S. Patent # 5,793,980; U.S. Patent # 5,917,835; U.S. Patent # 6,151,634; U.S. Patent # 6,487,663; U.S. Patent # 6,731,600. Other U.S. patents pending. All rights reserved. Helix, RealAudio, RealNetworks, 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.

2601 Elliott Avenue Seattle, Washington 98121 Phone: (206) 674.2700 Fax: (206) 674.2699 www.realnetworks.com

Helix Universal Server and Proxy, Version 15

Contents

1. Release Version ................................................................................................... 5

2. Operating System Requirements .............................................................................. 5

2.1 Windows 2008 Server .................................................................................... 5

2.2 Solaris 10 .................................................................................................. 5

2.3 Red Hat Enterprise Linux/CentOS 5 and 6 ........................................................... 5

3. 64-Bit Support .................................................................................................... 6

3.1 Memory Allocation ....................................................................................... 6

3.2 Default Memory Use ..................................................................................... 6

3.3 Changes to Default Memory Use ....................................................................... 6

3.4 Media File Size Support ................................................................................. 7

3.5 Log File Sizes on 64-Bit Applications ................................................................. 7

4. New Features in Helix Version 15.1 ........................................................................... 7

4.1 Virtual Hosting ............................................................................................ 7

4.2 Streaming Speeds up to 15 Mbps ...................................................................... 7

4.3 More CDN supported ..................................................................................... 7

4.4 Akamai RTMP Push Stream Naming ................................................................... 7

4.5 EIA-608 and EIA-708 Captions Support ............................................................... 8

4.6 Rate Parameters ......................................................................................... 8

4.7 Registry APIs .............................................................................................. 8

4.8 Content Management APIs .............................................................................. 8

4.9 API XML Response Updates ............................................................................. 8

4.10 HLS Updates............................................................................................... 8

4.11 Heartbeat Log ............................................................................................ 9

5. Known Issues in Helix Version 15.1 ............................................................................ 9

5.1 Vhost API will cause some memory leak and CA. .................................................. 9

5.2 Http Player number in monitor and logs mean http connection number with server. ...... 9

6. New Features in Helix Version 15.0.3 ........................................................................ 9

6.1 TS Multirate ingest support ............................................................................ 9

7. New Features in Helix Version 15.0.2 ........................................................................ 9

7.1 BuyDRM support for HLS clients ....................................................................... 9

7.2 Verimatrix API extension ............................................................................... 9

7.3 Amazon EC2 environment support .................................................................... 9

8. Major Issues Resolved in 15.0.2 .............................................................................. 10

8.1 Session Manager cannot support iOS6 .............................................................. 10

8.2 Adaptive HLS Content fails with stream switching while using Verimatrix player. ........ 10

8.3 When trying to playback some multirate .3gp files, the IOS .m3u8 header file is missing bandwidth data .................................................................................................... 10

8.4 ServerSidePlayList won't play back VOD and live with files encoded in HMP ............... 10

8.5 Segmented HLS TS content appears to change PID during segments ......................... 10

8.6 Lip sync issues on very long VoD files .............................................................. 10

8.7 Segmentation fault when play back with Realplayer ............................................ 10

8.8 Resolve.pl and uniquestacks.pl not working with v15.0.1 ...................................... 10

8.9 VOD file with IDR Frame cannot be played on iOS6 devices ................................... 10

9. New Features in Helix Version 15.0 ......................................................................... 10

9.1 MPEG-DASH support ................................................................................... 10

Helix Universal Server and Proxy, Version 15

9.2 MPEG-2 TS Live Broadcast Input ..................................................................... 10

9.3 HLS Push Upload to CDN .............................................................................. 11

9.4 HLS Support Updates .................................................................................. 11

9.5 Flash Push Upload to CDN and RTMP Server....................................................... 11

9.6 Flash/RTMP Streaming Support Updates ........................................................... 12

9.7 Time-Shifting for HLS Live Broadcasts ............................................................. 12

9.8 Verimatrix DRM Support for HLS Clients ........................................................... 12

9.9 Live Archiving APIs ..................................................................................... 12

9.10 SLTA Multirate Support ............................................................................... 12

9.11 Helix Administrator Updates ......................................................................... 12

10. Issues Resolved in 15.0 ........................................................................................ 12

10.1 RTMP and RTMPT issues ............................................................................... 12

10.2 MPEG-2 TS segments for multirate out of sync, causing shift failures ....................... 13

10.3 HLS Playback on some devices fail due to pathing issues (client doesn't support full path URLs) 13

10.4 ##@UBER=X comment used in master playlist files .............................................. 13

10.5 Unable to play multicast feed with Live RTP using Back Channel Multicast ................ 13

10.6 Others .................................................................................................... 14

11. Known Issues and Workarounds in Version 15.0........................................................... 14

11.1 Configuration file ...................................................................................... 14

11.2 DASH MPEG-TS .......................................................................................... 14

11.3 IP Binding ................................................................................................ 14

11.4 NTLM Authentication on Windows Server 2008 ................................................... 14

11.5 Installation Program ................................................................................... 14

11.6 Helix Administrator System .......................................................................... 15

11.7 Bookmarking ............................................................................................ 15

11.8 Broadcast Redundancy ................................................................................ 15

11.9 Content Distribution ................................................................................... 15

11.10 Fast Channel Switching ............................................................................... 15

11.11 Flash ...................................................................................................... 16

11.12 General Server and Proxy ............................................................................ 16

11.13 General Mobile Clients ................................................................................ 17

11.14 HLS Segmentation ...................................................................................... 17

11.15 Live ....................................................................................................... 17

11.16 Logging ................................................................................................... 17

11.17 Media Data Pipeline / Enhanced Rate Adaptation ............................................... 18

11.18 Multicast ................................................................................................. 18

11.19 QuickTime Player ...................................................................................... 18

11.20 Reduced Startup Delay ................................................................................ 18

11.21 SDPGEN .................................................................................................. 18

11.22 SNMP ..................................................................................................... 18

11.23 UDP Ports ................................................................................................ 19

11.24 Windows Media Support............................................................................... 19

Helix Universal Server and Proxy, Version 15

1. Release Version

Release Version: 15.1 Release Type: General Release Platform: CentOS5, CentOS6, RHEL5, RHEL6, Solaris10, Windows2008 Products:

Helix Universal Media Server 15.1 (64-bit only)

Helix Universal Media Server Professional 15.1 (64-bit only)

Helix Universal Mobile Proxy 15.1(64-bit only)

2. Operating System Requirements

2.1 Windows 2008 Server

Helix Server and Helix Proxy products are available as 64-bit applications on 64-bit versions of Windows Server 2008 R2. Service Pack 1 or later is recommended. The 32-bit versions of Windows Server 2008 and the 64-bit versions that predate R2 are not supported. File names for the application installers are the following:

Product Version Download Package File Name

Helix Universal Server 64-bit Mbrs-151-GA-win-64.zip

Helix Proxy Server 64-bit Mbpx-151-GA-win-64.zip

Note: The account that runs the server or proxy installation program

must have administrator privileges. The account that runs the server or

proxy does not require administrator privileges, however.

2.2 Solaris 10

Helix Server and Helix Proxy products are available as 64-bit applications on Solaris 10 Server running on Sparc hardware. File names for the application installers are the following:

Product Version Download Package File Name

Helix Universal Server 64-bit Mbrs-151-GA-solaris-10-64.zip

Helix Proxy Server 64-bit Mbpx-151-GA-solaris-10-64.zip

Note: If you plan to use the SNMP feature, apply update 6 or higher to

the solaris 10 operating system to ensure that the master agent

functions correctly.

2.3 Red Hat Enterprise Linux/CentOS 5 and 6

Helix Server and Helix Proxy products are available as 64-bit applications on Red Hat Enterprise Linux 5 and 6 Server. File names for the application installers are the following:

Product Version Download Package File Name

Helix Universal Server and Proxy, Version 15

Helix Universal Server for RHEL5/CentOS5 64-bit Mbrs-151-GA-linux-rhel5-64.zip

Helix Universal Server for RHEL6/CentOS6 64-bit Mbrs-151-GA-linux-rhel6-64.zip

Helix Proxy Server for RHEL5/CentOS5 64-bit Mbpx-151-GA-linux-rhel5-64.zip

Helix Proxy Server for RHEL6/CentOS6 64-bit Mbpx-151-GA-linux-rhel6-64.zip

3. 64-Bit Support

All Helix server and proxy products are available as 64-bit executable programs. As noted above, RealNetworks supports only the 64-bit executable program on certain platforms. At startup, the application indicates if it is 64-bit. You can also display this information using the –v startup option. For example:

Helix Mobile Server (c) 1995-2011 RealNetworks, Inc. All rights reserved.

Version: Helix Mobile Server (RealNetworks) (15.1.0.175)

(Build 234292/18525)

Platform: win-x86_64-vc10 (64-bit)

3.1 Memory Allocation

The 64-bit version has no practical limitations and is able to use as much application memory as the operating system can provide.

3.2 Default Memory Use

By default, the 64-bit version of a Helix server or proxy starts up with the following memory allocation maximum:

Up to 80 percent of physical RAM with an absolute limit of 1.6 GB.

For example, on a machine with 1 GB of physical RAM, the server or proxy may request up to 800

MB of memory. On a machine with 2 GB or 4 GB of RAM, it will request up to 1.6 GB of memory as needed.

3.3 Changes to Default Memory Use

For a 64-bit version of a product, the -m flag in the startup command changes the maximum memory available to the application:

On a 64-bit operating system, you may want to use the –m flag to set a higher maximum than the 1.6 GB set by default. For example, you may want to set application memory to 12 GB on a machine with 16 GB of physical memory.

Note: For 64-bit versions, the minimum value for the -m option is 512 MB.

More Information: Refer to the startup chapter in Helix Systems Integration

Guide for information about using the -m flag. That chapter also explains how

the server or proxy uses additional memory in the form of memory-mapped I/O.

Helix Universal Server and Proxy, Version 15

3.4 Media File Size Support

The 64-bit version of a server or a proxy on a 64-bit operating system can read and stream any size of media file. This allows for delivery of lengthy, high-bandwidth clips as well as large files that encode multiple bandwidths.

3.5 Log File Sizes on 64-Bit Applications

The 64-bit versions of the server or proxy support the creation of extremely large log files. This essentially makes the need to roll log files by time or file size optional. However, for practical reasons such as the time required to parse large log files, log rolling is recommended. The online help explains how to set file rolling for the following types of log files:

error log

basic access log

advanced logging templates that write reports to files

RSS logs for server statistics

4. New Features in Helix Version 15.1

The 15.1 update of Helix Server introduces the following features in addition to the earlier Release 15 features.

4.1 Virtual Hosting

Virtual hosting allows Helix Server to host content for separate media accounts. Request URLs for an account use DNS names that designate each account and its unique content.

4.2 Streaming Speeds up to 15 Mbps

Helix Universal Server Version 15.1 supports streaming speeds up to 15 Megabits per second for each client. This includes all supported media types (H.264/AAC, Flash, Windows Media, and so on) and all supported client types. The total outgoing bandwidth is limited by the available network bandwidth or any bandwidth limitation set on the Helix Administrator Connection Control page.

4.3 More CDN supported

The RTMP Push capability of Helix Server has been expanded. You can now push a live RTMP stream to Mirror Image (www.mirror-image.com) and Ustream (www.ustream.tv).

4.4 Akamai RTMP Push Stream Naming

How Helix Server names the live RTMP streams it pushes to the Akamai CDN has changed to accommodate Akamai stream name restrictions. The Akamai RTMP Push topic explains how to name uploaded streams to create the correct Akamai URL. The StreamParameter variable, which could previously be set in the configuration file, has been removed.

Helix Universal Server and Proxy, Version 15

4.5 EIA-608 and EIA-708 Captions Support

Helix Server supports the streaming of H.264 video that has captions/subtitles embedded using either the EIA-608 or EIA-708 standard. Captioning is supported for streamed content (RTMP or RTSP delivery) or segmented content (HTTP delivery for HLS and DASH).

4.6 Rate Parameters

For multi-rate content, you can use query string parameters to select a single rate, a maximum rate, a minimum rate, or an initial rate (previously supported for HLS clients). Rate parameters can be included in request URLs for HLS, DASH, Flash, and RTSP clients.

4.7 Registry APIs

The registry APIs allow you to use HTTP GET and POST directives to learn the status of Helix Server registry variables as well as to make changes to configuration values

4.8 Content Management APIs

User can use HTTP APIs to add and delete content to Helix Server mount points remotely. These APIs can be used to upload configuration information for virtual hosting accounts and add playlists for the server-side playlist feature.

4.9 API XML Response Updates

To maintain consistency with the virtual hosting APIs, the XML responses for other HTTP APIs have been changed. Each response includes a <returncode> element that indicates 0 for success or a numeric code that refers to a type of error that was encountered. Responses also include an <info> element that provides detailed information about the result. The following HTTP APIs are affected:

1) Broadcast archiving APIs.

2) Verimatrix DRM APIs.

3) BuyDRM APIs.

4.10 HLS Updates

The following changes have been made to Helix Server HLS operation:

Helix Server now supports pre-segmentation for on-demand content. This allows you to generate segments and playlists for clips in advance of the first media client request. The HLS general settings in Helix Administrator allow you to set a scan interval or initiate immediate segmentation for new content. The HLS source setup defines which on-demand mount points are enabled for pre-segmentation.

The section "HTTP Redirection" explains how to manage HLS clients that do not accept HTTP redirection to a playlist on an /m3ugen/ request.

The default value for HttpEnableGzip has changed from 1 to 0. This means that by default Gzip is notused when delivering playlists to HLS clients. You can change this variable manually to enable the use of Gzip, but this may conflict with certain HLS clients and encryption protocols such as BuyDRM.

Helix Universal Server and Proxy, Version 15

4.11 Heartbeat Log

The text file alivecheck.log is now created in the Logs directory to provide information about heartbeat check failures. This file is useful to RealNetworks support personnel for diagnosing Helix Server problems.

5. Known Issues in Helix Version 15.1

5.1 Vhost API will cause some memory leak and CA.

5.2 Http Player number in monitor and logs mean http connection number with

server.

6. New Features in Helix Version 15.0.3

6.1 TS Multirate ingest support

Helix Server v15.0.3 can support TS multirate ingest from DVEO, MediaExcel and Envivio encoder.

7. New Features in Helix Version 15.0.2

7.1 BuyDRM support for HLS clients

Helix Server can retrieve encryption key files from a BuyDRM VCAS server. It uses these key files to secure media segments generated for HLS clients. Clients that uses HLS streaming can then retrieve playlists and segments from Helix Server while obtaining the decryption key files from the VCAS server.

7.2 Verimatrix API extension

Before 15.0.2, Verimatrix API implementation doesn’t support multi-server environment. That is to say same clips in different servers may have different resource-id, that will cause trouble for customers.

The new API extension will handle above issue. It intends to let different server have same resource-id for same clip. Customer could update the resource-id mapping by modifying local map file or by using http call.

7.3 Amazon EC2 environment support

Helix Server support AWS Marketplace AMI which uses EBS storage from v15.0.2.

Helix Universal Server and Proxy, Version 15

8. Major Issues Resolved in 15.0.2

The issues lists below have been fixed in Helix Server v15.0.2.

8.1 Session Manager cannot support iOS6

8.2 Adaptive HLS Content fails with stream switching while using Verimatrix

player.

8.3 When trying to playback some multirate .3gp files, the IOS .m3u8 header

file is missing bandwidth data

Try to playback some of their multirate .3gp files, via HLS, the IOS .m3u8 header file is displaying bandwidth parameter as 0. So the file doesn't playback.

8.4 ServerSidePlayList won't play back VOD and live with files encoded in HMP

8.5 Segmented HLS TS content appears to change PID during segments

- Sometimes the video PID value in the same rate stream changes between segments

- Sometimes the same segments in two different rates have different video PID

8.6 Lip sync issues on very long VoD files

8.7 Segmentation fault when play back with Realplayer

8.8 Resolve.pl and uniquestacks.pl not working with v15.0.1

8.9 VOD file with IDR Frame cannot be played on iOS6 devices

9. New Features in Helix Version 15.0

9.1 MPEG-DASH support

Helix Server supports media clients that implement DASH (Dynamic Adaptive Streaming over HTTP). Like HLS clients such as the iPhone and iPad, DASH clients request media as a series of transport segments indexed to a playlist (.mpd file). Helix Server can support DASH clients using either MPEG-4 (also known as MP4 or ISO Base Media File Format) segments (.m4s files) or MPEG-2 transport stream segments (.ts files). Helix Server support Live and On-demand for DASH streaming but do not support server side playlist in this release.

9.2 MPEG-2 TS Live Broadcast Input

Helix Server can acquire an MPEG-2 Transport Stream encoded as H.264/AAC from a server or a multicast address, broadcasting the content to Flash, HLS, DASH, and RTSP clients. You designate the MPTS encoder source and can specify which program of the MPEG-2 stream to acquire. It can only support single program and single rate TS stream.

Helix Universal Server and Proxy, Version 15

9.3 HLS Push Upload to CDN

The HLS Push feature allows you to upload to a Content Distribution Network the live sources segmented for HLS clients such as the Apple iPhone and iPad. When a specified broadcast begins, Helix Server uploads the segment files, playlists, and key files to the CDN using HTTP posts. The HLS Push feature current supports uploads to the Akamai CDN.

9.4 HLS Support Updates

This release contains the following changes to the version 14 implementation of HLS support for iPhone and iPad clients:

The /iPhone-src/ mount point has been replaced by /segsrc/ as the default location for storing source files segmented for HLS clients. As in previous releases, you may continue to use any on-demand mount point to store H.264/AAC content sources for HLS segmentation.

The /iPhone/ mount point has been replaced by /Segments/ as the default location for storing transport files (.ts) and playlists (.m3u8) for HLS clients. The base path for the /Segments/ mount point is the Segments subdirectory of the Helix Server installation directory (not the Content subdirectory).

The /Segments/ mount point is designed to be used with DASH clients as well as HLS clients. Within the content directory, separate subdirectories correspond to the segment format (MPEG-2 TS for HLS clients). Segments and playlists for HLS clients are generated under the segment-specific subdirectory.

Archiving of segments and playlists for live broadcasts has been discontinued. To create an on-demand archive for a live broadcast, use the broadcast archiving feature to write the H.264/AAC live stream to an MPEG-4 (.mp4) file. Once the broadcast completes, move this file to an on-demand source mount point, such as (/segsrc/). Helix Server then segments the archive on the first HLS client request.

You can add the variable DisableAudioOnly to an HLS segment mount point configuration to turn off the generation of the audio-only stream for HLS clients.

The default for the SegmentNameRandomization variable has been changed to 0. This means that HLS segment files do not use segment name randomization in the form n-xxxxx.ts by default.

To enable support for Verimatrix encryption, the FSMount.segment_mount_point.MPEG2-TS_Output variable EnableEncryption has been changed to Encryption. It can have a value of none, aes128, or vcas.

Helix Server now supports HLS protocol version 3.

Background on HLS setup has been moved from Helix Media Delivery Platform Integration Guide to the help section "HLS Clients".

9.5 Flash Push Upload to CDN and RTMP Server

The RTMP Push feature can upload live Flash or Flash-compatible sources to a Content Distribution Network or another RTMP server. Broadcasts may be from a Flash encoder or any encoder generating H.264/AAC content. When a broadcast begins, Helix Server transmits the stream to the target server using RTMP. This feature has been checked on Akamai CDN.

Helix Universal Server and Proxy, Version 15

9.6 Flash/RTMP Streaming Support Updates

For Flash clients using RTMPT, you can use the RTMPIdent2 variable to set the address of a NAT firewall or virtual IP. This allows cloaked Flash clients to contact Helix Server through the firewall or VIP.

9.7 Time-Shifting for HLS Live Broadcasts

The Helix Server time-shifting feature allows an HLS client to seek backward and forward through a live stream similar to how it can move to different points in the timeline of an on-demand clip. Time-shifting requires a customized HLS client and is not supported for DASH clients. It is not available to Flash and RTSP media clients that receive copies of the actual encoder stream rather than stream segment files kept on disk. This feature require additional implementation in client side.

9.8 Verimatrix DRM Support for HLS Clients

Helix Server can retrieve encryption key files from a Verimatrix VCAS server. It uses these key files to secure media segments generated for HLS clients. A Verimatrix ViewRight client that uses HLS streaming can then retrieve playlists and segments from Helix Server while obtaining the decryption key files from the VCAS server.

9.9 Live Archiving APIs

The broadcast archiving feature now includes HTTP-based APIs that you can use to learn the status of streams being archived, as well as stop and restart the archiving process. All broadcast archives now include an XML file that records the stream information.

9.10 SLTA Multirate Support

SLTA has been enhanced to support streaming of multi-rate clips. The processes for setting up and running SLTA remain the same. If the input content is mp4 format, then “-fp” parameter is required.

9.11 Helix Administrator Updates

The Helix Administrator interface to Helix Server has been updated and reorganized to provide easier access to feature pages. Some pages have been moved to different categories and renamed. Additionally, Helix Administrator now includes a security feature that times out access to the interface after 15 minutes of inactivity. After the timeout expires, you will be required to enter your Helix Administrator username and password again.

10. Issues Resolved in 15.0

10.1 RTMP and RTMPT issues

10.1.1 RTMPT port 80 problems via proxy

There is a web proxy between client and Helix Server, when RTMPT playback via web proxy on 80 port, only one player can playback at a time.

Helix Universal Server and Proxy, Version 15

10.1.2 Helix Server fail to work with MComms Transcode for RTMP ingest

RTMP live failed to start on Helix Server when MComms Transcode is used as RTMP ingest

10.2 MPEG-2 TS segments for multirate out of sync, causing shift failures

For multirate live and SLTA streams, TS segments generated by Helix Server go out of sync after some time.

In short, the example shows that the TS files with the same numbers, which should be created at the same time, are not. E.g. at the time the listing was taken, the files being in creation were:

183k - File being created: 2234-49696.ts

26k - File being created: 2222-51025.ts

47k - File being created: 2228-66312.ts

491k - File being created: 2237-54674.ts

10.3 HLS Playback on some devices fail due to pathing issues (client doesn't

support full path URLs)

When testing HLS playback with a number of Honeycomb based tablets:

- Samsung 10.1" Tablet (Honeycomb 3.2)

- Sony Tablet (Honeycomb 3.2.1)

- Galaxy GT-P6800 (Honeycomb 3.2)

It was seen that content playback fails from Helix while worked from an Envivio/HTTP

setup. In monitoring the Helix Server logs it was seen that the Tablet appends the path to

the m3u8 file to the path IN the m3u8 file which then Helix Server responds with

a "404 File Not Found"

10.4 ##@UBER=X comment used in master playlist files

Replace “##@UBER=” with “#EXT-X-STREAM-INF” as the internal tag.

10.5 Unable to play multicast feed with Live RTP using Back Channel Multicast

Configure the server for Back Channel Multicast,start a Live RTP feed to the server (copy sdp to Content/rtpencodersdp/),configure player for Multicast transport only as below.

Player -> Preferences -> Connection -> Network Transports -> RTSP Settings

Helix Universal Server and Proxy, Version 15

Play the URL to activate the Live Presentation.

rtsp://server/rtpencoder/live.sdp

A message from the player appears stating "Bad transport, check your player preferences to ensure all network transports are selected."

10.6 Others

We have more resolved issues in this release, you can contact support team to get more details.

11. Known Issues and Workarounds in Version 15.0

Following sections explain known issues for Helix Server 15.0 and Helix Proxy 15.0.

11.1 Configuration file

Configuration file for Server v15.0 is not compatible with Server v14.3 because some structure has been changed, one special tool is required to convert v14.3 configuration file to v15.

11.2 DASH MPEG-TS

Only support single rate with on-demand mode.

11.3 IP Binding

11.3.1 IPv4 and IPv6 Binding for All Addresses

Helix Administrator does not accept an asterisk ("*") character to bind to all IPv4 and IPv6 addresses. To capture all IP addresses, add the asterisk value to the IPBindings list of the configuration file by hand. For example:

<List Name="IPBindings">

<Var Address_1="*"/>

</List>

11.3.2 IPv6 Binding for All Addresses on Red Hat Enterprise Linux 5

Binding to all IPv6 addresses (“::”) will prevent the RHEL5 Helix Server from starting.

11.4 NTLM Authentication on Windows Server 2008

On Windows Server 2008, NTLM user authentication may experience issues of basic functionality. NTLM authentication enables Helix Server to use the existing Windows NT database of user groups. It also allows access control of content through NTFS file permissions. RealNetworks recommends using the Basic authentication protocol if possible.

11.5 Installation Program

11.5.1 Windows 2008 Account Privileges

The account that runs the Helix Server or Helix Proxy installation program on Windows 2008 Server must have administrator privileges.

Helix Universal Server and Proxy, Version 15

11.5.2 Silent Installer

The silent/non-interactive installer option has been removed.

11.5.3 Configuration File Versions

Operating a Version 14 Helix Server or Helix Proxy with an earlier version of a Helix configuration file is not supported, and may have unforeseen consequences.

11.6 Helix Administrator System

1. Changing the name of a Transmitter Source via the Helix admin webpage requires a server restart to take effect even though the user will not be prompted to do so.

2. Some IPv6 addresses require the inclusion of square brackets “[ ]” to be accepted. If adding an IPv6 address does not work as expected, try adding brackets around the address. This is required for cDist.

11.7 Bookmarking

1. There are known issues using bookmarking with legacy origin servers and transmitters, which will prevent the client from connecting to the stream.

2. If serving media to RealPlayer clients, the BookmarkName must be “start”.

11.8 Broadcast Redundancy

When you send a live feed to Helix Server, a file name that has multiple periods generates multiple, alternative streams for broadcast redundancy. This means that a single, live feed is duplicated multiple times depending on the number of dots in the original file name.

11.9 Content Distribution

The default mount point must always exist for the content distribution feature to work as designed. If no "/" mount point exists in the Helix Server configuration file (rmserver.cfg) and content distribution is configured, the content subscriber sends the wrong URL to the content publisher when looking for content. The publisher therefore returns a 404 - File Not Found.

11.10 Fast Channel Switching

1. With Enhanced AAC+ or AAC+ content, switching between a live stream and either an on-demand clip or a simulated live stream delivered by SLTA fails to switch successfully. An error about non-compatible formats is logged.

2. The FCS session GUID will occasionally not get released by Helix Server.

3. Although 3GP content can have a reasonable amount of bit-rate variance while remaining switchable, RealMedia content requires a very close bandwidth similarity to support switching.

4. Issues exist serving multi-rate content when the client switches to a stream at a rate other than the highest rate.

5. There are known issues switching between .f4v files created by different encoders.

6. FCS-related parameters are not logged in the Helix Server access log for HTTP switch requests.

7. It is recommended that content for use with FCS be created with audio superblocking disabled. This can be done by adding the following attribute to the Audience section of the encoder’s job file:

Helix Universal Server and Proxy, Version 15

MaxPacketInterleavingDuration="0"

11.11 Flash

1. Flashgen requests for FLV files will generate an initialization error.

2. Helix Server cannot serve SMIL files and their internal links as part of a single RTMP session. As a result, pre-generated SMIL files cannot be served by RTMP when Helix Server validates requests using Helix Security Manager unless the internal links have been individually secured by URL Processor.

3. It is recommended that you run F4V files through the Adobe F4V Post Processor, which can be downloaded from Adobe. Although F4V content can be streamed without being processed first, it is less efficient to do so and could affect your server’s throughput capability.

4. The Helix Server supports AMF level zero. The following line should be added to any action scripts:

NetConnection.defaultObjectEncoding = ObjectEncoding.AMF0

5. MP3 container files are not supported for RTMP streaming.

11.12 General Server and Proxy

1. System time changes of more than a few seconds while the server is running, and particularly while the server is under load, can cause severe memory leaks and potential restarts. This sort of system time change may be triggered by NTP services, daylight savings changes, or simply by manual date/time changes. We recommend disabling these services on systems running Helix Server and Helix Proxy and making time adjustments manually during server down times or times of low load.

2. Time in Helix Administrator monitor does not reflect PC System time in certain time zones. The issue is observed where the time offset is not by a full hour. For example, if the Newfoundland GMT is -330, the server time is off by 30 minutes.

3. Enhanced rate adaptation never uses packet aggregation and PPM always does, regardless of the setting of the RDTPacketAggregation variable.

4. Helix Server will respond with a 501 error code if (and only if) an unknown RTSP verb is the first verb encountered in the RTSP session. This conflicts with the RTSP standard but it should have no significant impact.

5. Windows Servers on certain systems will not serve multi-rate content containing spaces in the name.

6. Setting a mount point using a Windows Network share may require connecting to the network drive via the same user that runs the Helix Server process, which is easiest to perform from the command line:

7. a. Open Command Prompt by Right-Clicking and select Run As Administrator

8. b. Run: “net use x: \\machine\winShare”

9. Helix Server will start up with certain port conflicts (such as RTSP and HTTP being the same), which will prevent normal operation. Ensure that you are not misconfiguring the server if modifying the configuration file directly.

10. The configuration file cannot have period (“.”) characters in list names.

11. You may see the following error on startup if running the server on Windows Server 2008:

access_ctrl: failed to resolve a hostname for rule 100

In this case, add the following access rule:

Helix Universal Server and Proxy, Version 15

<List Name="AccessControl">

<List Name="100">

<Var Description="Allow localhost access (do not edit)"/>

<Var Access="Allow"/>

<Var From="127.0.0.1"/>

<Var To="any"/>

<List Name="Ports">

<Var Port_1="any"/>

</List>

</List>

11.13 General Mobile Clients

1. Certain mobile handsets will not handle a live teardown correctly (accept the RTCP BYE that is sent). At the end of a live session, they must be manually closed by the user.

2. Playback of 3GP content on MotoRAZR always starts some number of seconds into the clip.

3. Certain Sony-Ericsson handsets will not play back from the Helix Server because of the existence of the line a=maxprate in the SDP files created by the server. This can be avoided by adding the variable <Var DisableMaxprate="1"/> to the ClientCapabilities list in the appropriate UAS file.

11.14 HLS Segmentation

1. HLS multi-rate files are always defined in the master playlist from the lowest bitrate to the highest. The iOS device will always attempt to play the first rate listed. As a result, it will always start with the lowest rate in the clip, and shift up from there. You may manually reorder this playlist (once segmented) in order to change the default selection.

2. Segmentation purging on Windows Server 2008 will work correctly only if Last Access Time Stamp is enabled. It is disabled by default to save system resources, and without enabling it, segment libraries will not get purged in the correct order. To enable Last Access Time Stamp on your Windows Server 2008, run the following command from a command prompt (with admin permissions):

fsutil behavior set disablelastaccess 0

11.15 Live

1. Helix Server will drop the RTP encoder video presentation when multiple SDP files referencing the same presentation are present in the SDP file directory.

2. In a scenario with many live feeds connecting to the server, some may not start successfully or may stop and restart again. This can be observed when Directory Scanning is turned off. Enabling Directory Scanning causes all the feeds to work as expected.

11.16 Logging

1. Helix Server and Helix Proxy don’t roll to new logs properly on SIGHUP. This is by design. The SIGHUP is interpreted by the server as a signal to RECONFIGURE the server. When the server is started, it creates the rmerror.log file and only when the first clip is played it creates the rmaccess.log file. After these log files are moved/renamed and a SIGHUP is sent to the server, the new files (rmerror.log and rmserver.log) will be created only after the first clip is played. They are not created until then. The goal behind having this feature (rotating the logs manually) is still achieved. The SIGUSR2 is interpreted by the server as a signal to restart the server and hence it creates the rmerror.log right away.

Helix Universal Server and Proxy, Version 15

2. Occasionally when a client selects the Default UAS, a superfluous error message will appear in the error log stating that the “Client's Buffer is too small for Predata.” This log message can be ignored.

3. The ERA/LRA TFRC log shows the Oversend Rate as higher than the value of MaxOversendRate. This is a logging error and can be ignored.

4. The variable %Client.*.Session.*.SessionStartTime% will log as UNKNOWN when used in customized logging templates. Use the variable %Client.*.StartTime% instead, which will give the same value.

5. Setting a customized logging template to broadcast to a multicast address using UDP isn’t working. Please select a different method for publishing log entries.

6. Logging to an inbound TCP port requires a restart after changing the configuration.

7. Logging to an outbound TCP port requires the use of an IP Address rather than a hostname.

11.17 Media Data Pipeline / Enhanced Rate Adaptation

If no Default UAS is found, unrecognized User-Agents will receive a 404 error in response to any DESCRIBE request.

11.18 Multicast

1. When configuring Scalable Multicast, VirtualPath values cannot be numeric only. For example, “2” won’t work, but “2a” will.

2. Multicast Pull Splitting will time out after 2 minutes. If you are using multicast, push splitting should be configured instead.

11.19 QuickTime Player

When playing on-demand media, at the end of the clip, the QuickTime Player will send a PAUSE request, followed by an OPTIONS request approximately 30 seconds later, and finally a TEARDOWN about 30 seconds after that. This means that access logs won’t get written until approximately one minute after the stream has ended, and that the connected_time logging field will record that excess amount. This should be kept in mind as logs are parsed, particularly if they are being used for billing.

11.20 Reduced Startup Delay

Setting the variable CPUThresholdToDisableRSD to 100 will roll the value back to the default of 65. The highest value the system will recognize is 99.

11.21 SDPGEN

Clients attempting to play an SDPGEN URL using HTTP Cloaking will receive a “Bad Transport” error.

11.22 SNMP

1. The SNMP v1 user name must be set to “public” for traps to function properly.

2. The Trap Interval value has no effect.

3. The Master Agent doesn’t return an error message if it is started with an invalid configuration.

4. The Master Agent prints an error when starting without a community string being configured. This error message should be ignored.

Helix Universal Server and Proxy, Version 15

5. Setting the trap values for CPU or Max Connections to zero doesn’t disable these traps. You must set them to a value which is high enough that is won’t be reached.

6. SNMP will not always return accurate results at higher server loads (>500 connections).

11.23 UDP Ports

The documented variable UDPResendPortRange, which is supposed to limit the UDP ports used for resends, is ignored. The resend range will obey the standard UDP port range, or if they are set, the variables MinUDPPort and MaxUDPPort.

11.24 Windows Media Support

1. Windows Media 9 live streams will not work if hosted from SLTA.

2. Windows Media Push Splitting fails if set up to use TCP on an IPv6 network.

3. Windows Media streams fail to connect to the Helix Proxy via an IPv6 network.

4. Windows Media clips will not play properly if clicked on in the Content Browsing window.

5. There are various logging errors that occur when playing MMS through the Helix Proxy.

6. Windows Media Player v11 no longer supports MMS.