[Ffmpeg-devel] DVR-MS bug (MP2 decoding)

[Michael Niedermayer]

Hi

On Mon, Apr 24, 2006 at 10:50:13AM -0500, John Donaghy wrote:
> > I get the source width/height from AVCodecContext* catched as this:
> >
> > video_codec = avctx->streams[vidTrackId]->codec;
> 
> Thanks for that.
> 
> 
> > >> So I assume it's MP2 and not AC3.
> > >
> > > You're right, I looked at it in GraphEdit and on my machine it chooses
> > > my InterVideo audio decoder for this file rather than the regular MPEG
> > > Audio Decoder. The properties dialog for the Intervideo decoder calim
> > > it is '2 speaker mode, Dolby Sound compatible (as opposed to
> > > stereo/mono). It says the format is MPEG2 and the attributes are
> > > 16bit/48k/1ch. I wonder what is different about this audio stream that
> > > causes it to pick the Intervideo decoder - maybe the 'dolby' setting?
> >
> > All I know is that it's not AC3. DScaler has an input type
> > MEDIATYPE_DVD_ENCRYPTED_PACK instead of MEDIATYPE_Audio, that could be
> > the difference.
> 
> I'm afraid I've got no more ideas about this. I looked at what the
> code was doing and the demuxer reports it as an mp2 stream which is
> presumably correct. Then the mp3 lib code makes a call to 'read_frame'
> which repeatedly calls 'decode_header' to try to find a valid header
> without success. libmad.a also fails in that it plays some strange
> noises instead of the real audio stream.

hmm, what happens if you dump the audio stream into a file and try to
play that with mplayer or ffmpeg?

and if that doesnt work, maybe post a few kb of that audio stream maybe
someone can spot something by looking at it ....

[...]
-- 
Michael

In the past you could go to a library and read, borrow or copy any book
Today you'd get arrested for mere telling someone where the library is