#11472: horizontal bar artifacts from near 0 value pixels.
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Reporter: jphowey | Type: defect
Status: new | Priority: normal
Component: ffmpeg | Version: git-master
Keywords: | Blocked By:
Blocking: | Reproduced by developer: 0
Analyzed by developer: 0 |
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Summary of the bug:
horizontal bars on output when input pixels are between 0.004 and -0.004.
Bars are the color of prior frames with a transform. They are exactly 16
or 32 frames prior (black if before frame 16). If multithreading is turned
off the bars are from 1 frame prior. Artifacts happen on specific RGB
colors, when artifacts are produced, turning the image black and white or
turning one or two channels black makes the artifact not show up.
How to reproduce:
I can provided source EXRs if requested. Render Linear EXRs at higher res
than HD. Tested creating the artifacts at UHD. Built a CMSTestPattern in
Nuke. Gained down to .06 with -0.03 offset. Flipped the image and merged
over it's self with a dither mask. after that I animated an offset going
from 0.01 to -0.02. Halfway through the animation the artifact happened.
{{{
% ffmpeg" -y -framerate 24 -pattern_type sequence -apply_trc bt709
-start_number 1000 -i "/Volumes/Public/RGS_0180_comp_HVE_v0034.%04d.exr"
-vf "format=gbrpf32le" -c:v prores_ks -profile:v 3 -pix_fmt yuv422p10le
-timecode 00:00:41:16 "/Volumes/Public/RGS_0180_comp_HVE_v0034_FullRes.mov
ffmpeg version
built on ffmpeg-118468-g19a2d26177 or ffmpeg-7.1 (tested both)
}}}
Patches should be submitted to the ffmpeg-devel mailing list and not this
bug tracker.
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Ticket URL: <https://trac.ffmpeg.org/ticket/11472>
FFmpeg <https://ffmpeg.org>
FFmpeg issue tracker
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