[FFmpeg-trac] #10532(avfilter:new): Color changes at w => 1280, h >= 578 with libplacebo filter on rgb source

[FFmpeg]

#10532: Color changes at w => 1280, h >= 578 with libplacebo filter on rgb source
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             Reporter:  nicol     |                     Type:  defect
               Status:  new       |                 Priority:  normal
            Component:  avfilter  |                  Version:  git-master
             Keywords:            |               Blocked By:
             Blocking:            |  Reproduced by developer:  0
Analyzed by developer:  0         |
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 Summary of the bug: Up scale, down scale or not scale, color changes with
 resolution through libplacebo.

 rgb24(testsrc), colorchart(gbrp), rgbtestsrc(rgba) are changed,
 yuv420p(smptebars) is not changed.

 How to reproduce:
 {{{
 % ffmpeg -f lavfi -i colorchart=d=2 -vf
 scale=w=1278:h=576:flags=lanczos,setsar=1 -crf 18 -pix_fmt yuv420p
 colorchart_scale.mp4 -y
 % ffmpeg -hwaccel_output_format vulkan -init_hw_device vulkan=vk
 -filter_hw_device vk -f lavfi -i colorchart=d=2 -vf
 hwupload,libplacebo=inputs=1:w=1278:h=576:upscaler=lanczos:format=yuv420p:range=tv,hwdownload,format=yuv420p
 -crf 18 -pix_fmt yuv420p colorchart_libplacebo.mp4 -y
 Color doesn't change.

 % ffmpeg -hwaccel_output_format vulkan -init_hw_device vulkan=vk
 -filter_hw_device vk -f lavfi -i colorchart=d=2 -vf
 hwupload,libplacebo=inputs=1:w=1280:h=576:upscaler=lanczos:format=yuv420p:range=tv,hwdownload,format=yuv420p
 -crf 18 -pix_fmt yuv420p colorchart_libplacebo_w1280.mp4 -y
 % ffmpeg -hwaccel_output_format vulkan -init_hw_device vulkan=vk
 -filter_hw_device vk -f lavfi -i colorchart=d=2 -vf
 hwupload,libplacebo=inputs=1:w=1278:h=578:upscaler=lanczos:format=yuv420p:range=tv,hwdownload,format=yuv420p
 -crf 18 -pix_fmt yuv420p colorchart_libplacebo_h578.mp4 -y
 Color changes.

 ffmpeg version N-111792-gf0b1cab538-20230821
 built on ... BtbN Auto-Build 2023-08-22 12:49
 }}}
 Patches should be submitted to the ffmpeg-devel mailing list and not this
 bug tracker.
-- 
Ticket URL: <https://trac.ffmpeg.org/ticket/10532>
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