[FFmpeg-devel] UDP multicasts mixed up on receive due to wrong bind()

Luca Abeni lucabe72
Tue Nov 11 08:20:25 CET 2008

Hi Baptiste,

Baptiste Coudurier wrote:
>>>> Everything we need are windows testers ;-)
>>> I run Windows on a regular basis. You need something testing, I'm all ears. :)
>> Just create a multicast stream with vlc (it should have some
>> wizard to do this) and then try to receive it with
>> ffplay udp://<multicast address>:port
>> Apply Jindrich's patch, and see if it breaks something. Then,
>> apply my patch and repeat the same experiment.
> Can we fix this issue ?

AFAIR, what we miss is a patch that works on as many systems as possible.
I think we arrived to the conclusion that the best thing to do is:
first, try to bind the multicast group; then, if the first bind fails,
try to bind INADDR_ANY. Both Jindrich's patch and my one are missing
the second part...

> I mean Linux has priority over win32 IMHO

At this point, I tend to agree with you (at least, windows people do
not seem to care about multicast)

> can someone give me a multicast address to test ?

I think you have to generate it (with vlc, for example, or you can
use something like
	ffmpeg -re -i ~/Videos/khalilah.mpg -f mpegts udp://
WARNING: the "-re" option is important, but only works with some input
files). Of course, you have to stream the multicast on a different
machine respect to the receiving one...


More information about the ffmpeg-devel mailing list