[FFmpeg-trac] #3794(swscale:closed): SWSCALE: Quantization Errors in Y Studio Range

[FFmpeg]

#3794: SWSCALE: Quantization Errors in Y Studio Range
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             Reporter:  troy_s      |                    Owner:  (none)
                 Type:  defect      |                   Status:  closed
             Priority:  normal      |                Component:  swscale
              Version:  git-master  |               Resolution:  invalid
             Keywords:  range       |               Blocked By:
             Blocking:              |  Reproduced by developer:  0
Analyzed by developer:  0           |
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Comment (by Balling):

 Replying to [comment:15 Balling]:
 > You can't be serious right now...
 >
 > The gradient in RGB has 256 gradations, while gradient in YCbCr limited
 only can have 235-16+1. Seriously??? I mean, this is just wow. Of course
 you will lose some grays in --> YCbCr!
 >
 > That is why SMPTE RP 219 defines everything for Y! And does not have
 Full range at all!
 >
 > Also if you looked accurately into the SMPTE RP 219 standard, you would
 find out that part of your ramp is 100% white (235, 128, 128) there and
 part is black or +Q. For Arib they just define the form of ramp, the SAME
 way SMPTE 219 does. It is 1440 pixels long, and 205 is black (or +Q) and
 205 are 100% white. See how it should have been done.
 https://www.youtube.com/watch?v=PqvEy5JLll4
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Ticket URL: <https://trac.ffmpeg.org/ticket/3794#comment:16>
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