[FFmpeg-trac] #8455(avcodec:open): libaom-av1 damages brightness range by switching yuvj420p to yuv420p

[FFmpeg]

#8455: libaom-av1 damages brightness range by switching yuvj420p to yuv420p
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             Reporter:  john123      |                    Owner:  (none)
                 Type:  enhancement  |                   Status:  open
             Priority:  wish         |                Component:  avcodec
              Version:  git-master   |               Resolution:
             Keywords:  libaom       |               Blocked By:
             Blocking:               |  Reproduced by developer:  0
Analyzed by developer:  0            |
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Comment (by john123):

 The new command line blob `ffmpeg -i in.mp4 -vf
 scale=out_color_matrix=bt470bg:out_range=pc,format=yuv420p -c:v libaom-av1
 -color_primaries smpte170m -color_trc bt709 -colorspace bt470bg
 -color_range pc -b:v 0 -cpu-used 8 out-470-709.mp4` yields the original
 level of brightness range clamping in the original bug report.

 Here's an example file that exhibits the usual color corruption during AV1
 conversion.  It's not identical to the original file, but neither of these
 files are some obscure thing - they're but just the standard output from
 video recording on an Android phone.

 I used ffmpeg to shrink the file down some in order to be able to attach
 it here, but the resulting failure when converting to AV1 is identical
 either way.
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Ticket URL: <https://trac.ffmpeg.org/ticket/8455#comment:19>
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