[FFmpeg-trac] #1162(avcodec:new): Possible regression in mpeg4 decoding.

FFmpeg trac at avcodec.org
Mon Apr 2 22:11:45 CEST 2012

#1162: Possible regression in mpeg4 decoding.
             Reporter:  dalecurtis   |                     Type:  defect
               Status:  new          |                 Priority:  normal
            Component:  avcodec      |                  Version:
             Keywords:               |  unspecified
             Blocking:               |               Blocked By:
Analyzed by developer:  0            |  Reproduced by developer:  0
 Currently, decoding/playing back this video in ffplay:


 (If link dies, it's the MP4 version under the "Download" link here:
 silverlight-5/silverlight-5-release-overview )

 Results in the following spew of errors before playback starts:
 [mpeg4 @ 0x2249600] hmm, seems the headers are not complete, trying to
 guess time_increment_bits
 [mpeg4 @ 0x2249600] my guess is 9 bits ;)
 [mpeg4 @ 0x2249600] Error, header damaged or not MPEG4 header (qscale=0)
 [mpeg4 @ 0x2249600] header damaged

 However this used to work without error... git bisect reveals commit
 as the culprit; specifically the removal of the forced width reinit:
 avctx->coded_width= 0.

 It's worth noting that ffplay only plays back this file because it ignores
 the return code of avcodec_decode_video2 (which is <0 in this case) and
 instead relies on got_picture=true.

 I've dug around a bit, but am unable to confirm if this is actually a
 regression or if the file is truly just corrupt. Can someone more
 knowledgeable take a look?

 Original ChromeOS bug report: http://code.google.com/p/chromium-

 Thanks in advance,

 - dale

Ticket URL: <https://ffmpeg.org/trac/ffmpeg/ticket/1162>
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