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

[FFmpeg]

#3794: SWSCALE: Quantization Errors in Y Studio Range
------------------------------------+-----------------------------------
             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           |
------------------------------------+-----------------------------------
Changes (by Balling):

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

Comment:

 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 wrong, 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
-- 
Ticket URL: <https://trac.ffmpeg.org/ticket/3794#comment:15>
FFmpeg <https://ffmpeg.org>
FFmpeg issue tracker