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libvlc stops video output (rtp stream) after content change ...

Posted: 29 Sep 2022 17:57
by Azamy
Hello, Everybody

If somebody might - Pls help us with our little problem:(

We are working under little project - embedded IPTV multicast player for Android TV box. OS - Andr.9

Suddenly we met a problem - libvlc stops video output while being on multicast igmp group. We made little investgation.

Everything looks like as following:

1. There is a server, which streams short videos to local network (many files with video on HDD) by multicast to group 239.255.1.1 , 2 , 3
2. From the beginning libvlc starts to render rtp stream from rtp://239.255.1.1:5004 without problem
3. when the server reaches end of current file, it sends rtcp message "Bye" , takes the next from disk and begins to stream it to the same igmp group with 3 sec delay between stop old file streaming - start new file
4. in this moment (end of current file) libvlc stops its output and doesn't start its output when server begin new file streaming. (Also I need to say that VLC from apk working without any problems)

Old file stream. -> RTCP "Bye" -> 3 sec delay (no any traffic) -> new file stream.

Also we see that each file's stream is going from different ports, like this:
the first file -> src - 192.168.7.240:XXXXX ->239.255.1.1:5004
the second file -> src - 192.168.7.240:YYYYY ->239.255.1.1:5004
the third file -> src - 192.168.7.240:ZZZZZ ->239.255.1.1:5004

In result - we see at the screen "freezed" the last frame of previous file, in the same time tcpdump shows that STB got rtp traffic of the second file over its interface. To start output again it needs to change group (TV channel) and return back. And it works till the end of current file.

What we have to do to solve this problem ? Which info will be useful for investigation ?

Re: libvlc stops video output (rtp stream) after content change ...

Posted: 29 Sep 2022 18:57
by RĂ©mi Denis-Courmont
I think you answered your own question, TBH. Don't send a BYE packet if you don't end the stream.

Also keep the same SSRC, the same clock source for RTP timestamps and same payload type.

Re: libvlc stops video output (rtp stream) after content change ...

Posted: 29 Sep 2022 20:44
by Azamy
No,no - it's not a reason of problem.

I blocked all rtcp traffic (port 5005) at Cisco switch by acl. No any "bye" or other RTCP packets were reached interface of STB - but libvlc stops its output. And Usual VLC from apk doesn't pay into attention any bye packets - when they were not blocked.