[FFmpeg-trac] #3801(undetermined:open): SWSCALE: Incorrect Values (+-1) in Full Range Conversion RGB to YCbCr

[FFmpeg]

#3801: SWSCALE: Incorrect Values (+-1) in Full Range Conversion RGB to YCbCr
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             Reporter:  troy_s       |                    Owner:  (none)
                 Type:  defect       |                   Status:  open
             Priority:  normal       |                Component:
                                     |  undetermined
              Version:  unspecified  |               Resolution:
             Keywords:  range        |               Blocked By:
             Blocking:               |  Reproduced by developer:  0
Analyzed by developer:  0            |
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Changes (by Balling):

 * status:  reopened => open

Comment:

 And here are first results. ffplay -video_size 1920x1080 -pixel_format
 yuv444p -f rawvideo -i ARIB_STD-B28_YCbCr_full.yuv -vf extractplanes=y

 shows that 75% Cyan is 151, 149, 32 while it should be (at least according
 to you) as in png 150, 150, 32, NICE! Next, 75% blue is supposed to be 14,
 224, 119 but it is 14, 223, 119 (DAH). Next: 75 % magenta is supposed to
 be 54, 202, 215 but actually it is 54, 201, 214.

 Next 100% Red is supposed to be 54, 99, 255 but it is actually 54, 98, 255
 (which causes that 254 issue).

 100% yellow is supposed to be 237, 0, 140 but is actually 237, 0, 139
 (again, 254 issue).

 And finally 75% yellow is supposed to be 177, 32, 137 but it is actually
 177, 32, 136.
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Ticket URL: <https://trac.ffmpeg.org/ticket/3801#comment:8>
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