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

FFmpeg trac at avcodec.org
Fri Jul 25 02:17:39 CEST 2014


#3801: SWSCALE: Incorrect Values in Full Range Conversion RGB to YCbCr
-------------------------------------+-------------------------------------
             Reporter:  troy_s       |                    Owner:
                 Type:  defect       |                   Status:  closed
             Priority:  normal       |                Component:
              Version:  unspecified  |  undetermined
             Keywords:  range        |               Resolution:  invalid
             Blocking:               |               Blocked By:
Analyzed by developer:  0            |  Reproduced by developer:  0
-------------------------------------+-------------------------------------
Changes (by michael):

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


Comment:

 The 2 png images are nearly identical, i see some +-1 differences from
 different rounding, which is clearly not what was meant in this bug,
 though if our rounding is suboptimal then such suboptmal rounding of
 course would be a bug that iam interrested in.

 The big vissible color difference is a fault in how the file was created,
 one of the pngs has a gamma of 1.0 the other does not. firefox displays
 them quite differently, other software shows them nearly identical,
 ignoring gamma i assume

 xview, displays this difference:
 ARIB_STD-B28_YCbCr_full.png is 1920x1080 PNG image, color type RGB, 8 bit
 test-full-444-out.png is 1920x1080 PNG image, color type RGB, 8 bit, file
 gamma 1.0000

 Also the difference png shows massive differences in areas that are bit
 exactly identical

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Ticket URL: <https://trac.ffmpeg.org/ticket/3801#comment:2>
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