[FFmpeg-trac] #225(swscale:closed): Converting from YUVJ to YUV lose contrast

FFmpeg trac at avcodec.org
Mon Jul 27 03:58:44 CEST 2015

#225: Converting from YUVJ to YUV lose contrast
             Reporter:  sghpunk      |                    Owner:
                 Type:  defect       |                   Status:  closed
             Priority:  normal       |                Component:  swscale
              Version:  git-master   |               Resolution:  invalid
             Keywords:  YUV/YUVJ     |               Blocked By:
  contrast                           |  Reproduced by developer:  0
             Blocking:               |
Analyzed by developer:  0            |
Changes (by michael):

 * status:  reopened => closed
 * resolution:   => invalid


 The yuvj_input.mkv file is identified as using yuvj and correctly
 converted by ffmpeg.
 mplayer seem not to support yuvj formats (see fmt-conversion.c
     // YUVJ are YUV formats that use the full Y range and not just
     // 16 - 235 (see colorspaces.txt).
     // Currently they are all treated the same way.

 Thus mplayer displays every file that is identified as yuvj as if it was
 yuv and thus shows higher contrast than players supporting yuvj. If now
 such yuvj file is converted to yuv mplayer shows a differece but this is
 not because theres something faulty in the convertion, both in and output
 look similar in players supporting yuvj.

 Now to make this a bit more complex, it could very well be that some files
 are misidentified as yuvj when actually they should be yuv but thats a
 whole different issue and if you suspect thats the case for some file,
 please open a seperate bug report for that.
 This bug report has become very unwieldy with all kinds of somewhat
 related information making it
 hard to find if issues remain in some cases. Opening new terse reports
 each with a clear reproduceable testcase should make fixing any remaining
 issues much easier and faster.

Ticket URL: <https://trac.ffmpeg.org/ticket/225#comment:27>
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