Filter "Speed: Forward only" seems to not consider changed Duration of Clips

What is your operating system?
Windows 11

What is your Shotcut version (see Help > About Shotcut)?

Can you repeat the problem? If so, what are the steps?
It is about the filter “Speed: Forward only”

I use it in an playlist project to either slow down…

or speed up…

some clips.

  • In case of slow down the clip is cut off earlier then it should be,
  • in case of speed up, the clip is at the end and then a gap exists in the project until the next clip starts.

It seems, that the changed duration of a clip resulting by slowing down/speeding up is not considered by Shotcut.

This is currently by design with no plans to change it. Filters are not able to change the playlist, timeline, or clip properties.

You will have your reasons to think like that, but as a user I cannot follow. Whenever I use a speed changing filter, it will have an effect on the duration of that clip.

So how is the filter supposed to be used?

The workaround is to adjust the clip duration by trimming (out point) and using Properties > Duration if needed to extend the maximum for the out point.

The “reason” is only that it is a lot of work and nobody has volunteered their time for free to make it work they way you expect.

This is the advice I have offered in the past. Yes, it is different than other tools. But I do not think it is too cumbersome.

Totally fine. No offense intended.

Yes, that works for both use cases. It’s just not directly intuitive to use it this way.

Thank you both.

Continuing the discussion from Filter "Speed: Forward only" seems to not consider changed Duration of Clips:

Hi, I came here to ask the same question as OP. I was wondering if you could expand on your workaround as I am a bit confused. After I trim it my video is timeline is about a minute. After 5 seconds, I want to accelerate over 5 seconds to 10x. Stay there for like 20 seconds, then decelerate over 5 seconds back to 1x. As soon as I increase speed the video gets compressed while playing but not on the timeline so every time I create a keyframe and adjust the speed it will shift any other keyframe. I don’t understand how changing the duration fixes that? Also, when I go to properties the duration is listed as the value of the untrimmed video.

My advice is to work from left to right. Adjusting a keyframe only affects the frames for future keyframes. So if you work from left to right, there are no “future” keyframes yet. When you are all done, and like the effect, then make one final trim to the clip to cut off any extra duration at the end.

Initially, yes. But you can change it to make it longer. Making it longer is only necessary if you are slowing the speed. If you are only making the speed faster, then, eventually, you will need to shorten the video.