[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
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Currently, decoding/playing back this video in ffplay:
http://download.microsoft.com/download/1/8/2/182AEF91-1DAE-493B-
BFF8-9BC6F85F5A3D/HDI_ITPro_Silverlight_mp4video_Silverlight5_Release_Overview.m4v
(If link dies, it's the MP4 version under the "Download" link here:
http://www.silverlight.net/learn/overview/what's-new-in-
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
http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=59e95fa4a8844d2abe7ddd7b8d269ea8d8eea17d
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-
os/issues/detail?id=28560
Thanks in advance,
- dale
--
Ticket URL: <https://ffmpeg.org/trac/ffmpeg/ticket/1162>
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