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

[FFmpeg]

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

Comment (by dtombs):

 That is the only way I have been able to reproduce it when doing a
 transcoding so far, since transcoding to vp8 involves the YUVJ -> YUV
 conversion.

 I have also reproduced the contrast loss when using ffplay. If I play the
 original yuvj_input.mkv using ffplay I get the contrast loss but if I play
 with mplayer it's full contrast.

 Here's output from ffplay, note the "deprecated pixel format" warning.

 {{{
 $ ffplay yuvj_input.mkv
 ffplay version N-55933-g8da23be Copyright (c) 2003-2013 the FFmpeg
 developers
   built on Sep  7 2013 14:51:01 with gcc 4.7 (Ubuntu/Linaro
 4.7.3-1ubuntu1)
   configuration: --enable-vdpau --enable-libvorbis --enable-libvpx
 --enable-zlib --enable-gpl --enable-postproc --enable-x11grab --enable-
 shared
   libavutil      52. 43.100 / 52. 43.100
   libavcodec     55. 29.100 / 55. 29.100
   libavformat    55. 15.100 / 55. 15.100
   libavdevice    55.  3.100 / 55.  3.100
   libavfilter     3. 82.102 /  3. 82.102
   libswscale      2.  5.100 /  2.  5.100
   libswresample   0. 17.103 /  0. 17.103
   libpostproc    52.  3.100 / 52.  3.100
 Input #0, matroska,webm, from 'yuvj_input.mkv':KB sq=    0B f=0/0
   Metadata:
     MAKER           : NIKON CORPORATION
     MODEL           : NIKON D90
     CREATION_TIME   : 2011-05-05 07:47:28
     ENCODER         : Lavf53.0.3
   Duration: 00:00:05.04, start: 0.000000, bitrate: 14463 kb/s
     Stream #0:0: Video: mjpeg, yuvj422p(pc), 1280x720, SAR 1:1 DAR 16:9,
 24 fps, 24 tbr, 1k tbn, 1k tbc (default)
 [swscaler @ 0x7f89681e8700] deprecated pixel format used, make sure you
 did set range correctly
    0.66 M-V:  0.035 fd=   0 aq=    0KB vq=  440KB sq=    0B f=0/0
 }}}

-- 
Ticket URL: <https://ffmpeg.org/trac/ffmpeg/ticket/225#comment:23>
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