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hellocatfood
Asked: 2010-12-18 04:34:38 +0800 CST

Can you do keyframed speed changes with video?

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I'm making a video and I want to do keyframed speed changes. That is, I want to have a video gradually get faster or slower at different points. I have been a user of kdenlive for awhile but have unfortunately found that is unable to do this. Can any recommend software that can definitely do this?

video video-editor effects

2 Answers

  1. Best Answer

    After a year of searching I've finally come across an answer. For this you'll need Blender. I'm using 2.56 beta.

    Open Blender and switch to the Video Editor

    Blender Video Editor

    Add a video to the editor

    Add a video

    To make things easier combine the audio and video clips (make a meta clip)

    Make a meta clip

    With the clip selected add a Speed Control effect

    Speed Control

    In the effect properties on the right-hand side first untick "Stretch to input strip length". Then hover your mouse over Speed Factor and Press "I" on your keyboard. This field will go yellow.

    Speed Control

    Move to a different point in the movie. Change the value in the Speed Control field and then hover your cursor over the field and press "I" key again. You'll see the graph on the left-hand side change to reflect your actions

    More speed changes

    Do this a few more times and you've just changed the speed of your movie using keyframes!

    There are many bug reports and feature requests in programs for easy keyframe editing of the speed of movies:

    Openshot Bug 524364 Bug 506096

    Kdenlive Bug 336 Bug 397 Bug 289

    VLMC Bug 205

    Novacut Bug 680865

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  2. This appears to be doable with the Kdenlive 21.08+ (21 Aug. 2021) “Time remap” feature:

    Kdenlive 21.08 is out with […] a new time remapping feature
    […]

    Time Remapping (Speed Ramps)

    The new Time Remap feature allows to keyframe the speed of a clip. timeremap gif example

    − https://kdenlive.org/en/2021/08/kdenlive-21-08-is-out/

    That gif is also all that docs.kdenlive.org has to say about the feature, but in short you can define keyframes, and set a clip’s speed before and after each key frame (including negative speeds to reverse the clip).

    You can also do these adjustments by dragging keyframes along 2 timelines, where the top is the input (the original clip) and the bottom timeline is the output. Spacing out 2 output keyframes differently from the matching input keyframes will adjust the clip’s speed between keyframes in the output.

    The effect can be found by right-clicking a clip and selecting “Time remap” − just below “Change speed”.

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