[FFmpeg-devel] Removing the "multicast=" tag from UDP URLs

Luca Abeni lucabe72
Mon Apr 14 17:09:41 CEST 2008

Hi Luca,

Luca Barbato wrote:
>> Ok; I hope I found a reasonable solution, see attached patches.
>> 0001-Remove-the-multicast-tag.txt removes the usage of the
>> "multicast=" tag, by using the (hopefully standard) IN_MULTICAST
>> and IN6_IS_ADDR_MULTICAST macros to understand if an address
>> is multicast. I added some "#ifdef"s to avoiding breaking
>> architectures that do not define such macros. The patch is tested
>> (and seems to work fine) on Linux.
> We should check on freebsd and netbsd IIRC.

Ok. I hope some *BSD user can test the patch (otherwise, we could force
people to test the patch by just committing it ;-). In the meanwhile, I
re-installed a mingw cross-compiler, and verified that the patch does
not break mingw compilation. Wine likes the resulting executables, and
the resulting ffmpeg.exe is able to correctly stream audio and video
over RTP.

>> 0004-Fix-receiving-from-SDP-with-unicast-destinations.txt fixes
>> the RTSP demuxer to pass the correct input port to the RTP protocol,
>> so that unicast SDP files can be correctly played.
> Ok

But this depends on the previous one... Or do you think that I can commit
it independently?

>> There is a remaining usage of "multicast=" in the SDP generator,
>> and I have some patches for removing it but I am not satisfied yet
>> with them (I do not want to resolve a host name for generating an
>> SDP description). The two attached patches actually fix a real bug
>> (while the SDP generator's patches are only a cleanup), so I think
>> they should be committed first.
> I took some time to look at the rtp -> udp protocol bridge and I think 
> that maybe we could avoid reformatting the url (I have a patch to get 
> the max_packet_size exposed on rtp but I'm not exactly happy with it)

I had a look at this issue in the past, but I am not sure if we really
want a patch like this... But maybe your patch is better than my previous
ideas ;-)


More information about the ffmpeg-devel mailing list