Performance became jumpy after upgrade

[LouF]

I upgraded my 22.11.25 version to the latest 25.10.31 and got very jumpy performance (unusable). Tried program restarts, system reboot without change. I have reverted back to 22.11.25, and it has returned to usual good performance; settings, such as Preview Scaling (360p) and no proxy were retained in each.

Has there been such a change to Shotcut or is there a setting I am unaware of to cause such load? I don’t see much/any discussion in the forum.

Running on Win10

Processor AMD Phenom™ II X6 1045T Processor 2.70 GHz
Installed RAM 8.00 GB
Storage 477 GB SATA SSD
Graphics Card AMD Radeon HD 6450 (384 MB)

[shotcut]

@LouF

Has there been such a change to Shotcut

Are you really asking if there has been a change in 3 years?

Shotcut - News

I do not know what you mean by “jumpy,” but it is working smooth for me.

@LouF

Preview Scaling (360p) and no proxy

That combination actually usually creates more work and reduces performance. That has not changed in the past 3 years. Read

Settings > Preview Scaling

The Preview Scaling setting may be used to reduce the resolution of video processing when you are using a fair amount of filters, transitions, and track blending. This may help with the performance during the editing process. [image] However, keep in mind that the source video or images must typically be scaled down to the designed preview scale, and that will have a processing cost. See Proxy Editing for the remedy to that. Proxy generates substitute clips at the same resolution as preview sc…

[LouF]

Feedback:

Turns out that the video in question has 60 fps, and the CPU simply cannot keep up (app grays-out; endless spinner icon; “program not responding” message etc…). I haven’t ran into this before, granted this a larger file than usual (2 hrs. instead of 1 hr.). No editing at all, BTW.

My 30 fps videos get by with slight chop.

Still, I was able to operate in my v22.11.25 with a 60 fps video as normal (which was good/tolerable). I don’t know what has changed.

[shotcut]

I see, it sounds like you are referring primarily to choppiness due to dropped fames of the 1x playback. Sorry to hear that.

Over the past 3 years besides numerous Shotcut changes there were major release updates to the core libraries that we use for the multimedia file reading & decoding (FFmpeg) and to make the UI in general (Qt). With the Qt version update Shotcut changed the way video is displayed on Windows from OpenGL (with an optional DirectX/3D 9 translation, see Settings > Display Method in the older version) to Direct 3D (with a hidden non-translating OpenGL fallback if you do not have Direct 3D 11). Yes, that is about as messy and complicated as it reads! Given the old age of your hardware I suspect this is the culprit. I regularly do comparisons of playback, memory usage, and export times on my systems from release to release. But I do not have any systems that I use anymore that are older than 10 years, and the oldest gets the least usage.

One test you can make is to compare the export times between the old and new versions using the same project and export settings (apples-to-apples comparison). That can reveal if there is a difference in the engine or the UI.

[LouF]

Thanks so much. That helps me understand what’s going on.

I’ve found the choppiness starts with v23.11.29, so I’ll have to keep this computer at version 23.09.29 (it’s been a sort-of workhorse).

BTW, the 23.09.29 gives a message during installation - not noticing anything missing that I use, which is mostly basics.