Speed forward filter not consistent

Bug
1

  • What is your operating system?

Windows 11

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

    25.10.31

  • Can you repeat the problem? If so, what are the steps?

I can repeat the issue in my own project. I have a large video in which I cut parts out and other parts that I speed up. I save the project, but when reopening it, some of the sped-up parts are all of a sudden linking to a different part in the video. Or turn out white. When I remove the speed forward filter, it resorts back to normal, but it means I have to redo the entire speed settings for that specific clip.

2

I just did a test where I opened up a 5 minute clip with a timecode and cut it into pieces. I applied the Speed Forward filter to some of the pieces. Then, I saved, closed, and reopened. The filters work the same after reopening.

So I was not able to reproduce a problem with my simple test.

Maybe there is something different with our environments.

Can you make a very simple example project that reproduces the problem and share it?

3

I wish I could - it’s very odd. I’m working with 658mb mp4 file. Some parts have no issues to be cut and sped up. Some apparently do. I did notice that all of my sped up filters seem to run down. So I set it for instance to 2x. but when I check the video, I see the 2.0 slowly dwindling down to 1.9, 1.8, etc. It doesn’t keep it at a steady 2.0x. If I add more keyframes it will go up/down based on what I’m choosing.

4

Maybe a screenshot of your project would have a clue. In particular, it would be good if we could see the keyframe panel in your screenshot.

5

So strange thing - if I have that clip in a different track, it is fine. If I move it down where the other clips are, it will screw up the timing after I reopen the project.

6

If I find a better way to reproduce this issue, I’ll post it.
As a question - is it better to use the SPEED setting in the clip properties to forward the clip vs the speed-forward filter? I understand that with the filter you can speed things up & down based on the keyframes vs the linear speed-up in properties.

7

This is exactly the difference. If you need a single, fixed, speed adjustment, then use the one in the properties panel. If you need to vary the speed over time, use the filter.

8

Perfect! That’s great advice. Thank you & Happy New Year.