#1582: Banding/discoloration in darker gradients when converting to rgb24
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Reporter: y3kcjd5 | Owner:
Type: defect | Status: open
Priority: normal | Component: swscale
Version: git-master | Resolution:
Keywords: swscale, | Blocked By:
bounty |
Blocking: | Reproduced by developer: 1
Analyzed by developer: 0 |
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Comment (by gdgsdg123):
== Sitrep from recent version ==
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Still occurs.
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Suggested workaround:
Always add `+full_chroma_int` to `sws_flags` (by `-sws_flags
+full_chroma_int` or `sws_flags=+full_chroma_int` in filtergraphs, or
both), unless speed is prefered over quality.
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Debug info:
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Build from:
https://zeranoe.com/builds/win64/static/ffmpeg-20190402-6aeaac3-win64-static.zip
Command:
{{{
C:\>ffmpeg -report -i "yuv420p10le.avi" -vframes 1 -compression_level 10
-pred mixed -pix_fmt rgb24 -sws_flags spline+print_info+accurate_rnd
".\-.png"
C:\>ffmpeg -report -i "yuv420p10le.avi" -vframes 1 -compression_level 10
-pred mixed -pix_fmt rgb24 -sws_flags
spline+print_info+accurate_rnd+full_chroma_int ".\+.png"
C:\>ffmpeg -report -i "yuv420p10le.avi" -vframes 1 -compression_level 10
-pred mixed -pix_fmt rgb24 -sws_flags spline+print_info ".\--.png"
C:\>ffmpeg -report -i "yuv420p10le.avi" -vframes 1 -compression_level 10
-pred mixed -pix_fmt rgb24 -sws_flags spline+print_info+full_chroma_int
".\-+.png"
}}}
Relevant files attached.
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Difference highlight:
(line 93 of the log files)
"+.log"/"-+.log":
{{{
[swscaler] chr srcW=720 srcH=418 dstW=1440 dstH=836 xInc=32768 yInc=32768
}}}
"-.log"/"--.log":
{{{
[swscaler] chr srcW=720 srcH=418 dstW=720 dstH=836 xInc=65536 yInc=32768
}}}
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Note:
"-.png" and "--.png", "+.png" and "-+.png", are bitexact respectively.
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Ticket URL: <https://trac.ffmpeg.org/ticket/1582#comment:15>
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