Bug 498337 - Rotoscoping shape doesn't match selection.
Summary: Rotoscoping shape doesn't match selection.
Status: RESOLVED FIXED
Alias: None
Product: kdenlive
Classification: Applications
Component: Video Effects & Transitions (other bugs)
Version First Reported In: 24.12.0
Platform: Mint (Ubuntu based) Linux
: NOR normal
Target Milestone: ---
Assignee: Jean-Baptiste Mardelle
URL:
Keywords: triaged
Depends on:
Blocks:
 
Reported: 2025-01-07 00:50 UTC by nuxttux
Modified: 2025-05-05 18:05 UTC (History)
2 users (show)

See Also:
Latest Commit:
Version Fixed In:
Sentry Crash Report:


Attachments
offset transform (6.54 KB, image/png)
2025-04-14 18:29 UTC, balooii
Details

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Description nuxttux 2025-01-07 00:50:45 UTC
SUMMARY
Using the Rotoscoping effect, the selection outlines do not align with the shape/selection.
Applies to animated and static reotoscoping.

Note: When animated, if you move/wiggle the selection, the offset may disappear.

STEPS TO REPRODUCE
1. Enable monitor "Show Edit mode".
2. Add video clip to timeline + color clip on top.
3. Add rotoscoping effect to color clip.
4. Make a selection on color using rotoscoping.
5. Observe offset.

-OPTIONAL-

6. Animate rotoscoping, ~5 frames at a time ( 3- 4 keyframes).
7. Return to first keyframe - (everything aligns).
8. Jump to next keyframe - (notice offset).

OBSERVED RESULT
The (red) outline of the selection/shape does not align with the Rotoscoping selection outlines.

EXPECTED RESULT
The (red) outline of the Rotoscoping's selection should align with with the selection/shape

SOFTWARE/OS VERSIONS
Windows: 
macOS: 
(available in the Info Center app, or by running `kinfo` in a terminal window)
Linux/KDE Plasma: 
KDE Plasma Version: 
KDE Frameworks Version: 6.9.0
Qt Version: 6.7.3

ADDITIONAL INFORMATION
In my experience, when animated - a simple wiggle of the selection restores the alignment.
Error seems to occur on smaller selections.
Error doesn't always occur.
Comment 1 emohr 2025-01-08 18:39:07 UTC
Thank you for reporting. I can confirm the issue. Following your steps. 

A small gap between the red rotoscoping out line and the color clip shape appear where the AV/clip shine through. In my case the color clip shape seems to be shifted 1 pixel downwards.
If you zoom into the monitor by one step the miss alignment is gone.
Comment 2 balooii 2025-04-14 18:29:14 UTC
Created attachment 180261 [details]
offset transform

Looks like its not specific to the rotoscope effect but more general. You get something similar when using transform and scale in a bit. Then you can see the offset on the red rectangle on the monitor.