[Libav-user] need advice on new player

Nicolas George nicolas.george at normalesup.org
Sun Feb 19 09:32:23 CET 2012


Le decadi 30 pluviôse, an CCXX, Deron a écrit :
> We are trying to work with all kinds of odd ball videos, and I have
> to accommodate either odd ball audio streams like != 48kHz, or two
> audio streams with mono samples instead of a single stereo stream,
> wrong sample size, or something that is too loud. Something like
> "-af resample=48000:0:2,channels=2,volume=-12,format=s16le" in
> mplayer would be used. What I'm not finding in ffplay is how to
> implement something similar.
> 
> The other minor case is when dealing with SD or 1080i video that
> needs to be scaled and/or clipped. It appears that ffplay includes
> video filters support. Correct? Am I just missing the support for
> the audio filtergraphs?

The FFmpeg system includes audio filtering, and a lot of filters that can do
what you require. The catch is that audio filtering is not implemented in
the command line tools: ffmpeg and ffplay. But it is still usable in a
roundabout way, using the lavfi pseudo-device:

	ffmpeg -f lavfi -i 'amovie=file.ogg, ...'

instead of:

	ffmpeg -i file.ogg -af ...

> I suppose the real question is, and no one but myself might be able
> to answer it but here goes, what would be the best place to base
> this on? It seems that modifying ffplay would be best?

I suggest adding it in libavdevice.

Ideally, MPlayer and ffmpeg should be made to be able to use libavdevice for
audio and video output.

Regards,

-- 
  Nicolas George
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