[Ffmpeg-devel] [PATCH] DVR-MS probe audio format - was DVR-MS bug (MP2 decoding)

Michael Niedermayer michaelni
Wed Mar 14 23:51:49 CET 2007


On Wed, Mar 14, 2007 at 02:47:10PM -0500, John Donaghy wrote:
> >> +    s->streams[stream_num]->codec->codec_tag = 0;
> >> +    av_free(pd.buf);
> >> +
> >> +    url_fseek(&s->pb, pos, SEEK_SET);
> >> +    asf_reset_header(s);
> >
> >uhm, i dont think this will work ...
> >try ffmpeg -f asf - test.avi <in.asf
> Do you mean setting the codec_tag to zero wont work? If so then you're


> >you could call a probe routine like that from av_find_stream_info() which
> >will take care of buffering all packets for you
> >
> Are you suggesting extending av_find_stream_info to generally handle
> the case where the  audio codec is unknown by probing it and
> attempting to identify it that way?

yes, the reason why iam suggesting, it is that you CANNOT seek back like
you do, the maximum seek back which is guranteed to be possible is the
size of the internal buffer but even just a single frame might be
larger, yes not all underlaying protocols support seeking ...

av_find_stream_info() contains code to deal with this by buffering all
demuxed packets ...

Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

No snowflake in an avalanche ever feels responsible. -- Voltaire
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