Created attachment 187501 [details] HSV Key effect malfunctioning This effect doesn't seem to be working properly. Still, when the "Compare effect" option is active for the clip, it "kinda wanna work" 😅 (i.e. it shows the keyed area in black, while still failing to show the clip below in the keyed area), as showed in the attached screenshot.
(in the rendered video, the effect does nothing)
tried both in trunk and 25.12.0 RC
Thanks for your report, I can confirm the issue. Not exactly sure where is the problem though. I am not sure avfilters can add an alpha channel in MLT. Bernd, were you able to make it work at some point ?
I've just made some tests with past versions of Kdenlive... I've found the effect worked fine from its introduction in 22.04.1, up until 24.05.2 (both in preview and final render). Starting from 24.08.0 on, it didn't work. The "Compare effect" black background in keyed areas was there all the time, though.