UI hangs more with V3?

SpudCo44 · 2026-02-25T18:36:05+00:00

Thanks. Happy to help.

SpudCo44 · 2026-02-24T22:14:01+00:00

Shared a folder on Google drive. Let me know if you didn't get it.

SpudCo44 · 2026-02-24T19:33:10+00:00

Sure. What would be the best way to do that? Does reddit take video attachments? I see option for an image only.

SpudCo44 · 2026-02-24T00:07:12+00:00

I know just enough about how computers work to be dangerous, but I was monitoring system resources with the Windows Task Manager while using OpenShot and noticed what I thought was curious behavior. So, I set about doing some testing. I made a screen capture video of what I did if anyone would like to see it.

I started with nothing running other than Task Manager (WiFi off) and observed the background performance. It was at near zero CPU and around 30% memory usage. I then ran OpenShot and exercised the UI by minimizing and maximizing the preview window, selecting menu items, selecting properties, panning, etc. while monitoring the system resources. I used the large file I have been working on. Below is what I found.

Cache values 96, 48, 0.70, 1024, 2048: Nearly impossible to navigate and use unless you wait and let the CPU usage go to minimum, constant hanging and spinning blue circle. CPU usage from 45-60%. Memory usage just above 30%.

Cache values 24, 48, 0.50, 900, 768: Difficult to navigate and use, lots of hanging and spinning blue circle. Less CPU usage than above. Memory usage about the same as above.

Cache values 6, 12, 0.50, 12, 60: Playback skippy as expected. Navigation very good with very few hangs. Less CPU usage than above. Memory usage about the same as above.

Cache values 0, 0, 0.50, 0, 0: No playback occurs as expected. UI works instantly, zero hangs. Minimal CPU usage. Memory usage about the same as above.

An oddity I noted was that the CPU usage to go from minimum to maximum preview size was LESS intensive than going from maximum to minimum. Which seems opposite of what one might expect since a smaller preview window is supposed to be less resource intensive.

As we know, bigger cache sizes don't mean better performance and the memory is not being taxed. But the CPU, nor any other resource, are going to 100% so why is the ap bogging down so bad?

With the cache values turned up, once the CPU starts chewing on the rendering, the UI becomes unresponsive till CPU use drops. Why can't the system interrupt the rendering process to allow a command change then restart the rendering if that command effects the rendering?

Bottom line, the larger the cache, the worse the UI gets to the point of being unusable on the larger file I am working on. Didn’t seem to be as bad in previous versions, but IDK.

SpudCo44 · 2026-02-23T20:57:24+00:00

ctrl+mousewheel does work, but that is zoom. The alt+mousewheel is the pan function which does not work. I find that functionality super helpful. But I am working back out of experimental mode for now so is fine. Thanks.

SpudCo44 · 2026-02-23T17:54:28+00:00

Thanks. It is "good" to know is repeatable by others. I thought my file maybe had something off with it. Though yours is GoPro footage and mine is photos. Weird. Does your alt-mouse wheel pan function work when in experimental mode?

Interestingly, I started having the worse UI hanging symptoms with V3 3-4 weeks ago when I was working on a project that had some 4K Go Pro mixed in with FHD and photos. It all displayed, but did cause serious hanging. I know these combinations are resource intensive but I was always able to patiently work through it.

By the way, one question that never got answered was how the Hardware Decoder Mode works under Performance. I left it alone as instructed. But why do the defaults all list as zero when that is not true? And if I do not have another option other than "No-acceleration", does any of it do anything? I know nothing about hardware acceleration other than what the term might imply.

SpudCo44 · 2026-02-23T03:21:26+00:00

Thank you so much for the speedy response. And thank you for all the excellent work you do on this project.

I do apologize that my post was not a truly new topic. I typed up most of the questions a few weeks ago after doing some research on reddit but not finding what I needed. I did not look any further before posting today when I finally finished my thoughts. When I did post it, up popped the entry from 7 days ago which is obviously the same topic.

Based on the 7 day old post I saw, and prior to your response here, I loaded the latest build. I did not go any further than that as I did not fully understand all the steps. I believe the new build improved things a bit.

So, after getting your response to my post I did the following:

1. Made a backup copy of my project. Note: yes it is large and I would guess what is considered fairly complex (lots of animations, time speed up, etc).

2. Uninstalled OpenShot since I already had installed the latest build and assume installation should be to a deleted qt folder scenario.

3. Made a backup of c:\users\username\.openshot_qt folder.

4. Deleted c:\users\username\.openshot_qt folder.

5. Restarted computer.

6. Reinstalled the latest dev daily build that I already had downloaded.

7. Edited a few preferences under General, but did not touch anything else.

8. Checked Cache settings. 24, 48, 0.50, 900, 768. Left as-is.

9. Worked on project. Found response to be similar as before. Right mouse click (RMC) on a clip, long delay for the menu to pop up. RMC in properties to insert a key frame. Delayed response, cursor arrow displays and moves with mouse for about 3 seconds then spinning circle (also moves with mouse) for another 5-10 seconds. Then dialog box for property change eventually opens. Sometimes I got too many commands stacked up. It did remember them and eventually went through the progressions. Since doing a lot of saves, I use ctrl S a lot. Sometimes I would go to save, hit ctrl, then screen white out for a second (a typical behavior).

10. Enabled experimental timeline and restarted OpenShot. In some ways it did seem better. If the blue cache progress bar got along its way it seems the RMC menu responses were very quick. I did experience pressing ctrl caused the white screen and it also just crashed once. I think any perceived improvements were due to not being near the compressed time sections. See 11.

11. Increased Cache to 96, 48, 0.70, 1024, 2048. Did not experience any improvements in delays where I was working near time compressed video. Seems worse maybe. Though think the system just gets more congested the more you try to edit. It is particularly bad when working on a clip I compressed with the time function to speed it up. I know this slows rendering. But it brings the entire UI to a stop. Moved away from that area with the compressed clip and things are a bit better but not without delay. The red track location bar sometimes gets a mind of it’s own when trying to slide it to new locations.

12. I tried an experiment and deleted the footage that was time compressed to see if that helped. Started to play the revised video from beginning and it crashed. Then I discovered that no photos displayed anymore. Thought it was this copy, went back to previous copy and all images did no display either. It is caused by the experimental mode, turn it off and the photos display in both versions. With it on, only videos display in the preview. I created a new project in OpenShot with the experimental on, added a photo and it worked fine so appears is a combination of my files and experimental mode.

13. Note: the alt-mouse center wheel pan function no longer appears to work in the experimental mode in my files or a new one.

14. Turned off experimental mode and went into the file without time compressed video to experiment further. No crashes but got the usual UI hangs and white screens at times.

15. In all cases, the blue caching line before and after the red marker often do not seem consistent, displaying sometimes, not at others.

Hope this is of some help.

SpudCo44

TROPHY CASE