Change Video Speed

[jay123210599]

Is there a way to slow down or speed up videos without losing quality? If so, how?

[huhn]

only video? just remux with the new frame rate that's it completely lossless.

with audio no.

[jay123210599]

only video? just remux with the new frame rate that's it completely lossless.

with audio no.

Why not with audio?

[huhn]

pitch correction is lossy so is resampling you need realistically both.

technically you can just play it back at double speed with out pitch correction or resampling but the result will be horrible.

[Z2697]

Nah I'd warp spacetime around my computer

[kurkosdr]

only video? just remux with the new frame rate that's it completely lossless.

with audio no.
It's also worth noting that there's a limit to how much you can remux with the new frame rate if broad compatibility with playback equipment is desired. For example, if you want to quadruple the speed of a video, you can't just remux a 30p video as 120p and expect most equipment to play it.

And as others have said, audio will have to be resampled and pitch-corrected too.

[Z2697]

Change the framerate in the VUI should work for most devices?
Or maybe just re-encode it with lossless codec / mode LOL

[FranceBB]

technically you can just play it back at double speed with out pitch correction or resampling but the result will be horrible.

Yep, although for simple 23,976 -> 25fps conversions it might just as well do the trick 'cause honestly, if we exclude the Doom9 "population", I'm sure that the overwhelming majority of users will fail to notice a pitch shift if they're watching a 4% speed-up without the reference.

So... Jay, we don't know what conversion you're trying to do (you didn't tell us) but if you want it to be done on the player side and therefore be lossless, you can easily just set it in the container and call it a day, which is super effective for 23,976 -> 25 and vice versa (25 -> 23,976). ;)