[FFmpeg-trac] #5936(avcodec:closed): Colored haze in mpeg4 decoding (purple, yellow, ...)

FFmpeg trac at avcodec.org
Tue Nov 22 05:00:52 EET 2016

#5936: Colored haze in mpeg4 decoding (purple, yellow,...)
             Reporter:  te36         |                    Owner:
                 Type:  defect       |                   Status:  closed
             Priority:  important    |                Component:  avcodec
              Version:  git-master   |               Resolution:  fixed
             Keywords:  asp          |               Blocked By:
  regression                         |  Reproduced by developer:  1
             Blocking:               |
Analyzed by developer:  0            |

Comment (by te36):

 To reproduce "OK" encoding with the haze problem.

 Re-encode example clip with fixed ffmpeg version, eg: to mpeg2.

 Re-encode with mencoder 1.2.1:
 mencoder-1.2.1 -ovc lavc -lavcopts vcodec=mpeg4:vbitrate=1500:ildct:ilme
 -o purple-haze-bug-mencoder.avi purple-haze-bug.ts

 produces the same large haze areas. This version of mencoder uses

 Re-encode instead directly with Lavc54.23.100:

 ffmpeg-lavc-54.23.100 -i purple-haze-bug.ts -vcodec mpeg4 -flags
 +ildct+ilme -b:v 1500k purple-haze-bug-ffmpeg.avi

 produces some small amount of haze on the edges but they don't tear
 across the whole picture. Maybe mencoder feeds some other parameters into
 lavc mpeg4 encoding.

 Recent versions of ffmpeg/mencoder do not produce visible haze anymore
 using the same encoding example.

Ticket URL: <https://trac.ffmpeg.org/ticket/5936#comment:12>
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