Bug 406935

Summary: 10-bit HDR (yuv420p10) videos look greyish
Product: [Applications] kdenlive Reporter: Linus Jahn <lnj>
Component: Rendering & ExportAssignee: Jean-Baptiste Mardelle <jb>
Status: RESOLVED UPSTREAM    
Severity: normal CC: fritzibaby
Priority: NOR Flags: fritzibaby: timeline_corruption+
Version First Reported In: 19.04.0   
Target Milestone: ---   
Platform: Debian unstable   
OS: Linux   
Latest Commit: Version Fixed/Implemented In:
Sentry Crash Report:
Attachments: Comparison between video player and kdenlive

Description Linus Jahn 2019-04-26 21:31:19 UTC
Created attachment 119655 [details]
Comparison between video player and kdenlive

SUMMARY

HDR Videos with 10 bit colours don't look correct: the colours are all a bit greyish. This happens in the project monitor and also in the resulting video, when rendered.

I also noticed that there's no option to use a 10 bit colourspace or pixel format (like bt2020nc/bt2020/smpte2084 and yuv420p10le), the output will always be in bt709 / yuv420p.

STEPS TO REPRODUCE
1. Add a yuv420p10le video (in my case: hevc (Main 10), yuv420p10le(tv, bt2020nc/bt2020/smpte2084), 3840x1600 [SAR 1:1 DAR 12:5], 25 fps)

OBSERVED RESULT
Colours look greyish.

EXPECTED RESULT
Colours should look like in the video player.

SOFTWARE/OS VERSIONS
Occurs in Kdenlive 18.12.3 (debian unstable) and 19.04.0 (flatpak from flathub).

This could also be a problem in mlt.
Comment 1 emohr 2019-04-27 18:53:48 UTC
Unfortunately MLT work in 8bit only. That must be the reason why you don’t get accurate colors.
Comment 2 Linus Jahn 2019-04-28 14:35:09 UTC
I found this commit in mlt: https://github.com/mltframework/mlt/commit/0b301cd249939d200df636d463d34e940f051b31
It's adding 10 bit support, but I think only for yuv422p16.
Comment 3 emohr 2019-04-29 17:42:36 UTC
You opened and issue on MLT: https://github.com/mltframework/mlt/issues/436. Seems to be an upstream problem. Thank you.