[FFmpeg-trac] #9407(ffmpeg:reopened): Broken Conversion: yuv444p10le to yuv444p

FFmpeg trac at avcodec.org
Mon Sep 6 04:32:12 EEST 2021


#9407: Broken Conversion: yuv444p10le to yuv444p
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             Reporter:  Michael      |                    Owner:  (none)
  Witten                             |
                 Type:  defect       |                   Status:  reopened
             Priority:  normal       |                Component:  ffmpeg
              Version:  unspecified  |               Resolution:
             Keywords:  pix_fmt yuv  |               Blocked By:
  yuv444p10le yuv444p 10-bit format  |
             Blocking:               |  Reproduced by developer:  0
Analyzed by developer:  0            |
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Comment (by pdr0):

 Apologies Michael, I read the ticket too quickly

 1) A YUV to YUV conversion is a no-op in terms of range - when in_range
 and out_range are the same.  You can explicitly list full in and full out,
 or limited in and limited out, or omit. The metadata does not carry though
 as you observed, so is not even required - which leads to the next point:

 2) What is important for current versions ffmpeg to work as expected , for
 actual results - is specifying the in_range before any YUV to RGB
 conversion (as you can see omitting produces wrong result), or out_range
 for RGB to YUV conversion.  ie. Always specify the range in the YUV
 direction. If nothing is specified, limited range is assumed.

 Maybe somewhere in the future when metadata works and passes correctly we
 won't have to do it this way. But this is the way it works now.

 3) The "multiple colors" is from dithering. Disable dithering

 ffmpeg -f lavfi -i color=0x7FFFD4:size=480x270 -vf
 scale=out_range=pc:out_color_matrix=bt709,format=yuv444p10le,scale=sws_flags=sws_dither=0=format=yuv444p,scale=in_range=pc:in_color_matrix=bt709,format=rgb24
 -frames:v 1 output.png
-- 
Ticket URL: <https://trac.ffmpeg.org/ticket/9407#comment:8>
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