Exported video fps not accurate


I have a video file that I have to reencode to a different format to work with my Hyperdeck Studio HD mini.
The input video has 25 fps and my target fps is 50 fps. After export to H.264 High Profile I can play it on my PC, but the Hyperdeck does not recognize it.
After further investigation (by looking at VLC Code informations) I could see that the fps value is mentioned as 50,005102. If I record with the Hyperdeck the value is exactly 50.
I tryed some other output codegs and framerates, but its always not exactly the value that I set in project settings and export settings.

After investigation on some other exported projects I could verify that problem also on all my projects. It even happens if my input files are 24 fps and my project/export setting is also 24 fps. The resulting value (in VLC) is then something like 24.000384 (webm) or 24.010563 (H.264 High Profile).

I hope that anybody can help me with my quite strange problem.

I use Version 21.09.20 and the problem occures with hardware (no GPU available, only CPU acceleration) and software encoding.


I am not an expert at answering questions, I am just doing some discussions. So sorry if you want an answer from me.

But one thing that’s running in my mind is that, why you want to just make a 25fps video 50fps?

If you do this, it will speed your project 2x then the original. And result in incorrect playback time.

If you are thinking that shotcut will make your video smoother by doing this, then, NO, It’s a misconception that you have.
Shotcut doesn’t create extra frames to make your video smoother, and that’s the same with many big softwares. You need an external plugin for that, which shotcut doesn’t support.

Thank you for including your version number! The frame rate problem is unique to that version. The bundled version of FFmpeg was updated which meant a change to API calls, but the MP4/MOV muxer wasn’t ready for prime time yet. Those issues were resolved in the October release. In theory, you could open your projects in the October version and export again to get constant frame rate files without any additional editing or configuration work.

Here are the release notes, with the fix being item 1:

And here is someone else reporting the same problem if you want more details:


no I don’t want to make my video smoother. I alrady know that shotcut (or ffmpeg) will simply duplicate the frames. I only wanted to have the video format already in the same format as my further streaming environment.
As I also wrote, if my input videofiles have the same fps as my output fps, it’s slightly off:

Thank you for this hint. I will try a newer version and check it again :+1:

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