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

John Donaghy johnfdonaghy
Fri Mar 30 21:02:07 CEST 2007


>
> hmm seems this is a missunderstanding, ive no problem with setting
> codec_id
> to CODEC_ID_NONE
> what i was complaining about was setting codec_tag to 0 which is wrong as
> that might not be the codec_tag stored in the asf file ...


I'd already removed the code that was setting the codec_tag (and the
frame_size) but it makes no difference either way. The proposed patch works
for ac3 audio streams ok but for mp2 audio I get the output below and then
ffmpeg crashes.

I think it is being caused by the fact that the initial audio frame reads
dont read complete mp2 frames because they dont know what the audio codec is
at that point. I could be wrong though and I dont know why this doesnt
present a problem to the ac3 decoder.

FFmpeg version SVN-rUNKNOWN, Copyright (c) 2000-2007 Fabrice Bellard, et al.
  configuration: --enable-liba52 --enable-gpl --enable-memalign-hack
  libavutil version: 49.4.0
  libavcodec version: 51.40.2
  libavformat version: 51.11.0
  built on Mar 30 2007 13:39:51, gcc: 3.4.4 (mingw special)
Input #0, asf, from
'g:/samples/Smallville__Ten-Can_09_02_2007_19_26_02.dvr-ms':
  Duration: 00:01:00.6, start: 0.000000, bitrate: 6516 kb/s
  Stream #0.0: Audio: mp3, 48000 Hz, stereo, 256 kb/s
  Stream #0.1: Video: mpeg2video, yuv420p, 720x576, 15000 kb/s, 25.00 fps(r)
Output #0, avi, to 'test3.avi':
  Stream #0.0: Video: mpeg4, yuv420p, 720x576, q=2-31, 200 kb/s, 25.00fps(c)
  Stream #0.1: Audio: mp2, 48000 Hz, stereo, 64 kb/s
Stream mapping:
  Stream #0.1 -> #0.0
  Stream #0.0 -> #0.1
Press [q] to stop encoding
[mp3 @ 006F2F40]incorrect frame size
[mp3 @ 006F2F40]incorrect frame size
[mp3 @ 006F2F40]Header missing skipping one byte.
[mp3 @ 006F2F40]Header missing skipping one byte.
[mp3 @ 006F2F40]Header missing skipping one byte.
[mp3 @ 006F2F40]Header missing skipping one byte.
[mp3 @ 006F2F40]Header missing skipping one byte.


[...]
> --
> Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
>
> Let us carefully observe those good qualities wherein our enemies excel us
> and endeavor to excel them, by avoiding what is faulty, and imitating what
>
> is excellent in them. -- Plutarch
>
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