[FFmpeg-devel] [PATCH] Implement an option in ffmpeg to make it print the output SDP and exit

[Stefano Sabatini]

On date Wednesday 2008-11-12 00:01:14 +0100, Stefano Sabatini encoded:
> On date Tuesday 2008-07-22 02:25:37 +0200, Michael Niedermayer encoded:
> > On Tue, Jul 22, 2008 at 01:49:02AM +0200, Stefano Sabatini wrote:
> [...]
> 
> Ehm, sorry for the slow reply...
> 
> > > On the other hand I'm not sure it is possible to implement an SDP
> > > muxer.
> > > Indeed the SDP issued by ffmpeg has to know *all* the RTP output
> > > streams:
> > > 
> > > stefano at geppetto ~/s/ffmpeg> 
> > > ffmpeg -t 0 -i ~/test.flv -sdp -f rtp rtp://localhost:5008 -f rtp -acodec libmp3lame rtp://localhost:5004 2> /dev/null
> > > v=0
> > > o=- 0 0 IN IPV4 127.0.0.1
> > > t=0 0
> > > s=No Name
> > > a=tool:libavformat 52.17.0
> > > m=audio 5008 RTP/AVP 0
> > > c=IN IP4 localhost
> > > b=AS:64
> > > m=audio 5004 RTP/AVP 14
> > > c=IN IP4 localhost
> > > b=AS:64
> > > 
> > > so it's not possible to write a muxer, because this for definition
> > > only knows one output file.
> > > 
> > > Any idea? Otherwise I propose to implement the already proposed -sdp
> > > option.
> > 
> > make rtp support multiple streams
> > 
> > something like:
> > -f rtp rtp://localhost:5008,localhost:5004
> 
> So what about something like this:
> ffmpeg -i audio1.mp2 -i audio2.vorbis -acodec pcm_mulaw -acodec libmp3lame -f rtp rtp://localhost:5004,localhost:5008 -newaudio
> ?
> 
> In order to print the sdp we could do something like:
> ffmpeg -i audio1.mp2 -i audio2.vorbis -acodec pcm_mulaw -acodec libmp3lame -f sdp rtp://localhost:5004,localhost:5008 -newaudio
> 
> The problem with this approach is that we can't specify the SDP
> output.
> 
> Maybe a better solution could be:
> ffmpeg -dest localhost:5004 -i audio1.mp2 \
>        -dest localhost:5008 -i audio2.ogg \
>        -acodec pcm_mulaw -acodec libmp3lame \
>        -f sdp test.sdp -newaudio
> 
> which would need another field (for example "dest") in AVCodecContext.

Forget about this last one, the syntax is wrong and I think it is
better to use the filename string to express that anyway, something
like -f sdp rtp://localhost:5004,localhost:5008/test.sdp but I need to
think more about it.
 
> Ideas are very welcome.

Regards.
-- 
FFmpeg = Fiendish & Frenzy Maxi Portable Energized God