FPS and audio sampling/bitrate changing on export

Great piece of software, this. I’ve hardly scratched the surface.

I’m confused about FPS, aka frame-rates.

  1. I have 3 old videos to combine into one. They’re all in this format: AVI, 640x480, 25fps. The audio is stero, 24KHz, 48 kb/s.
  2. So, before adding them as media to my project, I set the project’s Video Mode to 640x480, 25fps. (I have to make a Custom Video Mode, as the standard 640x480 is set to 29.97 fps or something).
  3. Add in my old videos.
  4. Export. I’m using H.264 Baseline Profile.
  5. But - this is what I don’t understand. The export defaults to 29.97003 fps (or something close to that). The audio doesn’t even offer me 24KHz as an option.
  6. If I then go back into Settings/Project/Video Mode and set the frame-rate to 25fps, all my markers change position. Has the project somehow ignored my 25fps setting?

Background question: surely there’s no point in exporting old video like this at a higher frame-rate (or audio sampling rate) than it already has? It’s not like it’s an analog original, which could be resampled in higher quality - it’s already digitalised. Or am I wrong?


Click on the Output panel (it’s on the top-left side of timeline, above track names) and open Properties panel, that is the project mode that is used currently, if it’s 29.97 you probably changed it by mistake early on even if you created the 25fps one.

Export should default to exactly project video mode, this also makes me think the video mode is currently 29.97.

Correct, exporting at a different frame rate best case scenario just uses more space and worst case it ruines fluid motion as the 25 fps are spread over the 29.97 to fill up.

For audio I do not know but I assume any conversion will lose some details.

Also correct, any re-edit to a digital video that is not lossless will likely lower quality (or best case remain like the original), unless you consider cosmetic enhancements like sharpening or adding saturation “higher quality” (sometimes they do improve perceived quality so depending on source type I would not exclude it completely).

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