Bug 512943

Summary: Blur effects issues with alpha channel
Product: [Applications] kdenlive Reporter: Gabriel Gazzán <gabcorreo>
Component: Video Effects & TransitionsAssignee: Jean-Baptiste Mardelle <jb>
Status: REPORTED ---    
Severity: normal    
Priority: NOR    
Version First Reported In: unspecified   
Target Milestone: ---   
Platform: Other   
OS: Other   
Latest Commit: Version Fixed/Implemented In:
Sentry Crash Report:
Attachments: blur issues on clips with alpha channel
test project with images used

Description Gabriel Gazzán 2025-12-04 15:50:31 UTC
Created attachment 187336 [details]
blur issues on clips with alpha channel

I just saw that the effects in the blur category aren't capable of correctly handling the alpha channel, in one way or another.

To exemplify it, please look at the attached video.

I've detected mainly two kinds of problems:
1. Edge handling (straight/premultiplied).
2. Not being able to extend the limits of the clip to accommodate the new pixels generated by the effect.

As I could see, all of those effects suffer from the first problem, while most of them also suffer from the second one.
Comment 1 Gabriel Gazzán 2025-12-04 15:53:21 UTC
Created attachment 187337 [details]
test project with images used