Kdenlive Pre-Rendering is Broken. I tried disabling some effects applied to my media, but it doesn’t help either. I already reported this as a bug on the KDE Bug Website a long time ago starting version 23.04. Looks like the bug persisted across 23.04.1 and now 23.04.2.
For anyone else reading this, the Bugzilla entry can be found here: 470237 – Kdenlive 23.04.1 Pre-rendering is STILL broken.
It may take a while for the kdenlive developers to get around to the bug report so it’s best to remain patient until then.
@RJS205 and I just finished a long discussion about this with an interesting find: The culprit in his setup was the title clip - take it off the timeline and preview rendering works!
Even with a single simple title clip in the timeline, preview render fails. The error message is libpng warning: iCCP: known incorrect sRGB profile so something must have changed in melt about the accepted color profile, or the way Kdenlive passes the title clip on to melt.
The bug report is being updated reflecting this find as we speak …