Now before you quickly jump in and say: Premier got an update... Use handbrake...

What I'm asking none of the big players seem to support. Rendering a video that's frame rate changes through the course of it run time.

There are three line in wikipedia for VFR. One of the sources says: "More modern formats like MPEG-4 allow variable frame rates as well, where the timebase itself changes between parts of the file. However, most tools don't support that directly"

Are there any programs that fully or partially support this?

  • Can you give us any more information on what you are trying to accomplish with a variable frame rate video? In general, there aren't many good uses for them as they are a pain to try to keep in sync since the frame buffer has to run at different timing. Ultimately, it's display is most likely going to be simplified to a constant frame rate anyway and the only real savings would be a minimal savings for storing long displayed images once vs having tween frames that simply say nothing changed. It's pretty rare for it to really be worth the complexity.
    – AJ Henderson
    Commented Jan 18, 2019 at 3:41
  • My understanding is that VFR was more a side effect of older cameras that couldn't necessarily maintain constant frame rate and didn't want to have dropped frames, so instead they just saved frame timing.
    – AJ Henderson
    Commented Jan 18, 2019 at 3:43
  • What I'm mainly trying to accomplish is greater understanding on how to create a VFR file. I have a Adaptive-Sync display and I would like to try it out on a something I created. Then further down the line I have some projects that I'd like to use their native frame rates as well as CG elements. I have been looking for documentation on this subject, so any links would be appreciated. Commented Jan 18, 2019 at 15:42
  • I'm not sure what you mean about using native frame rate as well as cg. The cg would be rendered at the same frame rate as the video.
    – AJ Henderson
    Commented Jan 18, 2019 at 17:14
  • Sorry, I'll clarify. Some GoPros don't have supported for 24 FPS. My phone is locked to NTSC. When recording in UHD some cameras only do it in 24 FPS. And in the CG world you can virtually have any frame rate you want. So for the CG side it's easy: animate the timings of frames I want, then render an image sequence. S Commented Jan 18, 2019 at 19:50

1 Answer 1


You could render the scenes to single files and combine them in ffmpeg to one .mp4 container. Allthough Indont know why you would want that.

  • How? The concat command uses the first video's frame rate to set the output Concatenated video's frame rate and it's constant. Commented Dec 30, 2018 at 19:13

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