Sometimes changing clip speed shrinks it too much

I am compiling multiple clips together over music. I speed them all up to 50x as each clips is anywhere from 6 mins to 25 mins long… but sometimes, and it’s not consistent, I type in 50x in the properties of the clip and it shrinks it extremely small so it’s only a sliver of what it was on the timeline.

Hope I’ve explained this sufficiently. Am I doing something wrong or might this be a bug?

Thanks in advance.

EDIT: I might have figured out that if I type in 50 in the box and hit “apply” instead of using the enter key, it won’t happen. :woman_shrugging:t2:

For me it always works by pressing Tab (so it’s a quick finger move instead of moving and aiming with the mouse).

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EDIT 1 April
So it’s still doing it repetitively, regardless of if I use the enter key, tab or manually press the apply button. It’s gotten to the point of being counterproductive to actually making the project. I definitely think this is a bug.

I can record a short video of it happening if that would help. I’m just not sure how to upload it here.


You can use this button to upload a video in your message:

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Thank you! Here it is. Sorry my camera is covering up the top of the properties box but I’m sure most are familiar with it. Thanks again.

I agree… you’ve got a pesky bug. Unfortunately, I am not able to reproduce it. I wonder if the bug is specific to your clip, or something about your project. For anyone who is able to reproduce this, would you be willing to create a minimum project and media that can reproduce the problem? Zip it up and send it to me so that hopefully I can recreate the problem.

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Thank you… it actually happens on most projects I speed clips up. I make music reaction compilations and I always put “the making of” each video at the end. It’s clips of the production and editing process of the video showing how I made it… but they’re all sped up. I compile all the recordings I made while making the video… there usually are anywhere from 10 - 12 recordings and they average anywhere from 6 mins to 25 mins long. Then I compile those together over a cover version of the song I made the video about… so the entire “making of” portion is as long as a song.

It’s happened across multiple versions of the software but seems to be more prolific the last month or two.

I’m not sure if this extra information will help, but wanted to give as much detail as possible. You can see any of these videos on my YT channel - WonderMommaOG, if you want to see what the finished product is supposed to look like. I have lower third labels on each part… so when that changes, it’s a new recording.

From your screen recording I noticed that when the problem appears the properties panel is completely blank, but after you close and reopen Shotcut, it’s filled correctly. I assume the blank properties also mean the program doesn’t know the clip duration so after you do 50x, it’s 50 times zero (null length) which makes it bug to zero frames long.

I wonder if this is simply the properties panel not updating for the clip.
Can you try to keep an eye on the values in the properties panel next time this happens? If it’s blank, like in this screenshot, try to click on any other video and then click back on your clip. Usually this forces a UI refresh so it should be filled correctly (unless the bug is more complex than this and I’m just way off).


I absolutely will keep an eye on that. If necessary, I’ll post another video when I go to do the making of portion of the current project I’m working on. I’ll turn off my camera as well.

Something else I forgot to mention… I notice that if I apply a speed to a clip and go back to it later to change the speed… in the speed box, sometimes it has a value of 1… and not the number I changed it to. That’s how I know it will shrink it too much if I change it again. Not sure if this is useful info but wanted to mention it.

I should be able to post an update in 2-3 days.

Excellent observation. This is almost certainly the cause of the speed problem. Now we need to figure out why the properties are not being populated. Has anyone else recreated this? I wonder if it is unique to the files that @WonderMommaOG is using. If anyone can help me recreate that properties problem, I’m sure I can fix it.

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The next time you do this operation, as an experiment, wait for a while to see if the properties information fills in after some time. Maybe there is a delay for the information to fill in and you are changing the speed before it is populated.

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Will do. I will try to record it and post it here.

So I just made the “making of” video for the current project I’m working on and of course, it worked fine. No buggy behavior whatsoever. :sweat_smile: Murphy’s law.

I will be making another in 4-5 days and will post an update if it does it for the next project. I might try to just throw one together this weekend to see if it happens again.

Ok, so I got it to do it again. It looks like it has to do with the program generating audio waveforms ? Check the message that pops up mid left side of the screen above the timeline at 1:25 - 1:26. 09endcomm is the clip that it happened with. I had to change the speed a few times to accommodate the music track. But the third time I changed the speed the glitch happened. Then I pressed cntrl Z twice to undo it.

Maybe all I have to do is wait for that “done generating audio waveform” process to finish and it will fix it?

Hope this helps.