Bug? Can't set export frame rate?

Windows 10, Shotcut version 22.12.21

When I try to export the project to MP4 with frame rate 20 frames/sec,
the frame rate always jumps back to 249 frames/sec, which was the rate
originally used in first try of project (reworking accidental
slow-motion recording).

I was able to export the original 240 frames/sec clip to 20 frames/sec MP4.

I’ve attached the project.

PS: It seems the project setting is overriding the advance frame rate setting??
Without any indication in the UI as to what’s happening?

OSTIV_cleanup.mlt (5.8 KB)

Just curious… Is that a typo?

I don’t think the frame rate is expressed in Hertz (Hz). I always see in f/s or frame/second
The only value that I see in the Export tab that use Hz is the Audio Sample rate. But a sample rate of 20Hz or even 249Hz seams pretty low.

Apologies, frame rate. 249Hz was slow-motion, 60Hz is USA TV rate.
20Hz is to average slow motion and minimize the flicker of projected slides.
Corrected the question…

Technically hertz is also good enough to use instead of fps, altough it’s usually referring to a physical object, something like this TV can do 60Hz, monitor 144hz etc. I don’t think it’s a mistake strictly from the definition:

The hertz (symbol: Hz) is the unit of frequency in the International System of Units (SI), equivalent to one event (or cycle) per second.

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There’s a 3x limit to how smaller than video mode you can export the project, so at 240fps the limit is 240/3 = 80fps. To overcome this you can set the poject’s video mode to something smaller (like 60 fps, or just straight to 24) and then you’ll be able to export this.

I also had the same problem a while back but as long as there’s a workaround I was fine with it but I still disagree with the limit.

Worst is the UI bug: don’t allow the user to change the frame rate, then immediately reset it without explanation. Next, why are the project settings limited? I ended up completing the export at 24Hz (after changing the project settings, just because it was the closest available option)…

Settings > Video Mode > Custom
Or, select Timeline > Output and then click Edit in Properties

A 240 fps video is usually intended to be used for slow motion in a 60 fps or lower project. You can only achieve that by - in addition to some speed effect - changing the project Video Mode and not by Export > Advanced (that button should caution you).

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