[FFmpeg-user] Multiple ffmpeg instances failing to subscribe to separate audio streams

Adam Nielsen a.nielsen at shikadi.net
Wed Dec 22 04:30:47 EET 2021

> We have been initially working with the 2110 decode example on the
> github site (https://github.com/cbcrc/FFmpeg) and have been
> successfully streaming media with it. We have evolved our design and
> would like to operate with multiple media streams.

The set up is probably a bit complex for anyone to be able to quickly
reproduce.  Can you simplify it for debugging purposes?  e.g. remove
the SDP file and stream from a URL directly?  Ideally you want the
minimum number of components in play that demonstrate the problem
(which will also tell you which component is at fault, if the problem
goes away once you remove that part).

I am wondering whether it's some issue around multicast and the
subscription/unsubscription messages getting mixed up.  Can you look at
the local system's IGMP subscription list (e.g. /proc/net/igmp) and
confirm that the subscriptions aren't dropping out when you're losing

You could try streaming from two different IP addresses instead of just
the one to see if this makes the problem go away.  If it works from two
different IPs but not two streams from the same IP, that would confirm
that it's probably an issue related to the multicast unsubscription
messages being sent at the wrong time.  But if you get the problem with
only one stream per IP address you can probably rule out IGMP as the

Sorry I couldn't be more helpful but it's a bit of an involved set up
to reproduce locally for testing.


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