Bug 453881

Summary: Time Remap : Gradually change speed between keyframes (speed ramp)
Product: [Applications] kdenlive Reporter: heecks
Component: Video Effects & TransitionsAssignee: Jean-Baptiste Mardelle <jb>
Status: CONFIRMED ---    
Severity: wishlist CC: admin, fritzibaby, m8oxu4nv3, silash35
Priority: NOR Keywords: triaged
Version First Reported In: 22.04.1Flags: fritzibaby: Brainstorm+
Target Milestone: ---   
Platform: Ubuntu   
OS: Linux   
Latest Commit: Version Fixed In:
Sentry Crash Report:

Description heecks 2022-05-16 10:47:09 UTC
SUMMARY

The Time Remap feature cannot be used to make a speed ramp effect, which is for me the ability to gradually change speed between two keyframes. 

STEPS TO REPRODUCE
1. Create a keyframe with speed=100%
2. Later in the clip, create another keyframe with speed=200%

OBSERVED RESULT
When the first keyframe 100% is hit, the playback speed goes instantaneously to 200%.
When the second keyframe 200% is hit, the playback speed goes instantaneously to 100%.

EXPECTED RESULT
The playback speed should increase gradually between the two keyframes : speed should be 150% between the two keyframes. Ideally, this should be controlled with bezier curves... 

Ok to be fair, the first keyframe is actually [speed before=100% ; speed after=200%] and the second keyframe is [speed before=200% ; speed after=100%] so the observed result makes sense. But I think everybody would expect a "ramp" effect here. Even the documentation is mentioning speed ramp : https://docs.kdenlive.org/en/effects_and_compositions/effects.html#time-remapping-speed-ramps.


SOFTWARE/OS VERSIONS
Linux: Kubuntu 22.04 
KDE Plasma Version: 5.24.4
KDE Frameworks Version: 5.92.0
Qt Version: 5.15.3
Comment 1 emohr 2022-05-16 18:19:41 UTC
Speed ramp from one keyframe to the next according a curve is not possible at the moment. This is due to MLT. So I change this issue to wishlist.
Comment 2 Julius Künzel 2022-07-30 18:59:59 UTC
*** Bug 442221 has been marked as a duplicate of this bug. ***
Comment 3 Julius Künzel 2022-07-30 19:09:12 UTC
*** Bug 457034 has been marked as a duplicate of this bug. ***