Source Specific Multicast Not Supported (?)

[GScharfofMars]

System info

Operating System: Ubuntu 16.04 LTS
Shaka Packager Version: v2.0.0-1d6a2de-release

Issue and steps to reproduce the problem

The following is an address redacted snippet from a test script. The redacted address streams have been shown to exist and be accessible to the host via other programs such as vlc and multicat.

Packager Command:
STREAM_SRC=XX.XX.XX.XX
INTERFACE=YY.YY.YY.YY
STREAM_ADDR=ZZ.ZZ.ZZ.ZZ
STREAM_PORT=PPPPP

./shaka-packager --v=1
in=upd://${STREAM_ADDR}:${STREAM_PORT}?source=${STREAM_SRC}?interface=${INTERFACE}?reuse=1,stream=audio,init_segment=audio_init.mp4,segment_template='audio_$Number$.m4s',playlist_name=audio.m3u8,hls_group_id=audio,hls_name=ENGLISH
in=upd://${STREAM_ADDR}:${STREAM_PORT}?source=${STREAM_SRC}?interface=${INTERFACE}?reuse=1,stream=video,init_segment=h264_init.mp4,segment_template='h264_$Number$.m4s',playlist_name=h264_.m3u8
--hls_master_playlist_output h264_master.m3u8

The result is:
./testPackager.sh
[0222/181854:INFO:demuxer.cc(89)] Demuxer::Run() on file 'upd://REDACTED?source=REDACTED?interface=REDACTED?reuse=1'.
[0222/181854:INFO:demuxer.cc(161)] Initialize Demuxer for file 'upd://REDACTED?source=REDACTED?interface=REDACTED?reuse=1'.
[0222/181854:VERBOSE1:status.cc(72)] 5 (FILE_FAILURE): Cannot open file for reading upd://REDACTED?source=REDACTED?interface=REDACTED?reuse=1
[0222/181854:ERROR:packager_main.cc(470)] Packaging Error: 5 (FILE_FAILURE): Cannot open file for reading upd://REDACTED?source=REDACTED?interface=REDACTED?reuse=1

https://google.github.io/shaka-packager/html/tutorials/live.html indicates that "source" is an optional clause for the upd "file" option.

Additional Info:
Inspection of source code (udp_options.cc) did not reveal any evidence that the "source" clause of the input spec is parsed or stored in the UdpOptions object instance, nor does the method used to join the IGMP group in udp_file.cc appear to be consistent with the method of joining an SSM group.

[kqyang]

@GScharfofMars For UDP options, source and interface mean the same thing. Either one can be used to specify the UDP multi-cast interface address. What do you put in source and interface options respectively? And what is the option you fed to vlc?

Also, the separator between different options is &. Sorry for not mentioning it in the document. I'll update the document to reflect that.

So the UDP file name should be something like:

upd://${STREAM_ADDR}:${STREAM_PORT}?source=${STREAM_SRC}&reuse=1

Please try and let us know if it works.

[GScharfofMars]

@kqyang

First, thanks for jumping in. I appreciate the support.

Source=interface surprises me a little.
I did try using & (escaped to & for bash) as the separator, to no effect.

Our environment is configured to use IGMP V3 Source Specific Multicast. VLC style mrls are in the generalized form of

udp://ipV4addressOfStreamSource@ipv4MulticastStreamAddress:port multicat also has an extension, /interface=ipV4AddressOfEth0 , and so with shaka-packager I was using interface=ipv4AddressofEth0 and source=ipV4AddressOfStreamSource.

Using vlc/multicat, I can observe IGMP message traffic with tcpdump. If the streamSourceAddress is specified, additional records indicating such are put into the IGMP join message, and the switch responds by sending the stream. If the streamSourceAddress is omitted, an IGMP message is sent without those records, and the switch declines to send the stream.

Summary, using tcpdump -vvv decode, REDACTIONS-IN-CAPS:

Success:
igmp v3 report, 2 group record(s) [gaddr MULTICAST-ADDRESS-OF-STREAM allow { ADDRESS-OF-STREAM-SOURCE }] [gaddr MULTICAST-ADDRESS-OF-STREAM to_in { ADDRESS-OF-STREAM-SOURCE}]

Failure:
igmp v3 report, 1 group record(s) [gaddr MULTICAST-ADDRESS-OF-STREAM to_ex { }]

Using shaka-packager, I see no IGMP messages sent of any flavor, under any combination of udp file names, including upd://addressOfSource@MulticastAddressOfStream:Port, nor do I see any way to supply the addressOfSource so as to propitiate the switch.

[kqyang]

@GScharfofMars Emm.. It seems that I had a misunderstanding of the meaning of source and interface. I thought they were the same. Do you have any documentation on UDP multicast explaining these addresses?

So we are not handling source correctly. We'd love contributions if you know how to fix it. Here is the code setting up the socket: https://github.com/google/shaka-packager/blob/master/packager/file/udp_file.cc#L171.

[GScharfofMars]

The reference I see coming up on the Web all the time is UNIX Network Programming, Second Edition, by W. Richard Stevens (Prentice Hall, 1998). Chapter 19 on "Multicasting".

I thought I had a copy on my shelf, but I'm not seeing it since the last time I cleaned my office. :(

My curiosity motivates me to try my hand at fixing it, but I won't be able to engage until later next week.

[kqyang]

Great. I'll assign it to you and add it to v2.1.0 milestone (which is targeted in the end of March). Let us know if anything changes. Thanks for your help.

[fatpelt]

@GScharfofMars if you can't get to it let me know. i have a working prototype

[GScharfofMars]

I've been sidetracked at work, and haven't even cracked open the lid on this. If you have something that works, by all means, I cede the coding stick to you. Thanks.