Bug 510507

Summary: Apply LUT: [filter avfilter.lut3d filter51] Unexpected return format
Product: [Applications] kdenlive Reporter: skywalker
Component: Video Effects & TransitionsAssignee: Jean-Baptiste Mardelle <jb>
Status: RESOLVED FIXED    
Severity: normal CC: balazs
Priority: NOR    
Version First Reported In: 25.08.2   
Target Milestone: ---   
Platform: EndeavourOS   
OS: Linux   
Latest Commit: Version Fixed/Implemented In:
Sentry Crash Report:
Attachments: Screenshot of the error.

Description skywalker 2025-10-11 21:40:15 UTC
Created attachment 185703 [details]
Screenshot of the error.

SUMMARY


STEPS TO REPRODUCE
1. Import a video
2. Use 'Apply LUT' effect on the video
3. The error will show.

OBSERVED RESULT
Showing a warning:
Apply LUT
[filter avfilter.lut3d filter51] Unexpected return format

and the applied LUT has no effect.

EXPECTED RESULT


SOFTWARE/OS VERSIONS
Linux:  EndeavourOS
KDE Plasma Version: 6.4.5
KDE Frameworks Version: 6.18.0
Qt Version: 6.10.0

ADDITIONAL INFORMATION
Please see the attached screenshot.
Comment 1 Terényi, Balázs 2025-10-28 07:58:13 UTC
Same here on recently updated OpenSuSE Tumbleweed with Kdenlive 25.08.2. The stdout when the error appears on the GUI in my case is:

[swscaler @ 0x7fd440584c40] Unsupported input (Operation not supported): fmt:yuyv422 csp:bt709 prim:(null) trc:bt709 -> fmt:rgb24 csp:gbr prim:(null) trc:bt709
MLT: "[filter avfilter.lut3d ] Cannot get frame from buffer sink"
MLT: "[filter avfilter.lut3d ] Unexpected return format"
Comment 2 Jean-Baptiste Mardelle 2025-10-28 08:21:58 UTC
Most probably your system uses FFmpeg 8.0. This requires MLT's git master version including this commit to fix the issue:
https://github.com/mltframework/mlt/commit/708caef19bee18d08965e78752a62d6ae7a470fa
Comment 3 Terényi, Balázs 2025-10-28 09:53:03 UTC
I built the MLT master and it works. Thank you for the info.
Comment 4 skywalker 2025-10-29 08:30:42 UTC
Just two days ago, I again opened the project in the installed version of Kdenlive 25.08.2 after updating the EndeavourOS and the error were gone!! After that I continued working on the project in the installed version of Kdenlive 25.08.2, but no error regarding the 'Apply LUT' filter has occurred. I haven't used MLT's Git Master version as you recommended because I just saw a few minutes ago that the problem was fixed. Anyway, the filter is working now. But there is another problem, probably a bug which I have reported separately. Thanks for your help.