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Intel QSV decodes AV1 grain synthed video differently compared to libaom and dav1d #2945

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netphils opened this issue Jun 10, 2022 · 0 comments
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bug win Windows

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netphils commented Jun 10, 2022

System information

Issue behavior

Describe the current behavior

I noticed abnormal noise while playing AV1 grain synthed video with the media player built in Windows, so I tested it with ffmpeg.
First, encode a AV1 video with grain synth on SVT-AV1.
ffmpeg -i input.mp4 -c:v libsvtav1 -preset 3 -g 600 -c:a copy -svtav1-params "tune=0:film-grain=5" "av1_with_grain_synth.mp4"
Then, decode the video with av1_qsv, libaom and libdav1d.
ffmpeg -c:v libdav1d -i .\av1_with_grain_synth.mp4 -ss 0 -t 3 -an dav1d.mp4
ffmpeg -c:v libaom-av1 -i .\av1_with_grain_synth.mp4 -ss 0 -t 3 -an libaom.mp4
ffmpeg -c:v av1_qsv -i .\av1_with_grain_synth.mp4 -ss 0 -t 3 -an qsv.mp4
Last, compare the PSNR between.
Dav1d and libaom:
ffmpeg -i dav1d.mp4 -i libaom.mp4 -lavfi psnr="stats_file=psnr.log" -f null -
[Parsed_psnr_0 @ 000001b2a06eee40] PSNR y:inf u:inf v:inf average:inf min:inf max:inf

Dav1d and qsv:
ffmpeg -i dav1d.mp4 -i qsv.mp4 -lavfi psnr="stats_file=psnr.log" -f null -
[Parsed_psnr_0 @ 00000220353b3980] PSNR y:49.638876 u:53.171929 v:54.094582 average:50.606395 min:49.217772 max:52.414425

libaom and qsv:
ffmpeg -i libaom.mp4 -i qsv.mp4 -lavfi psnr="stats_file=psnr.log" -f null -
[Parsed_psnr_0 @ 0000028aa236eec0] PSNR y:49.638876 u:53.171929 v:54.094582 average:50.606395 min:49.217772 max:52.414425

PSNR other than infinite shows there are difference between QSV decoded video and libaom/dav1d decoded videos.

Describe the expected behavior

QSV decoded video should be exact the same as libaom and dav1d, PSNR should be infinite.

Thanks for any kinds of help.

@netphils netphils added bug win Windows labels Jun 10, 2022
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