[FFmpeg-trac] #9085(avcodec:reopened): JPEG: YCCK too green

FFmpeg trac at avcodec.org
Sun Mar 21 06:56:34 EET 2021

#9085: JPEG: YCCK too green
             Reporter:  Balling     |                    Owner:
                 Type:  defect      |                   Status:  reopened
             Priority:  normal      |                Component:  avcodec
              Version:  git-master  |               Resolution:
             Keywords:  mjpeg cmyk  |               Blocked By:
             Blocking:              |  Reproduced by developer:  0
Analyzed by developer:  0           |

Comment (by pdr0):

 Replying to [comment:4 Balling]:
 > I tested in Photoshop 2021: no alternative icc profile produces such
 insane colours and removing colour management at all also does not produce
 the colours as in ffmpeg. So it is not ICC.

 Actually this is completely explained by ICC

 You can strip the profile in imagemagick or similar, and you get same
 results as non color managed, or ffmpeg (too green) , or any other non
 color managed tool

 convert.exe Channel_digital_image_CMYK_color.jpg -strip strip.png

 Or you can convert cmyk to srgb and you get same as reference on any sRGB
 display. (USWebCoatedSWOP.icc is the profile most often used for cmyk)

 convert.exe Channel_digital_image_CMYK_color.jpg -profile
 "USWebCoatedSWOP.icc" -profile "sRGB2014.icc" cmyk_to_srgb.png

 You can read png tags with tweakpng, jpeg tags with jpegsnoop, or
 imagemagick identify, or exiftool

Ticket URL: <https://trac.ffmpeg.org/ticket/9085#comment:14>
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