How to re-encode a 120fps (or higher) MP4 from my Samsung Galaxy to a 30fps (example) so it plays on Windows like it does on the Samsung

Question

I have some high fps slow-motion videos (mp4) that I've recorded on my phone, but when I copy them to windows and play them back, they play at the normal speed (or they play really fast), unless I slow down playback but this isn't a good result.

What I'd like to do is re-encode (if that's the right word) the video to a standard fps (such as 30) to get a longer video (keeping all the frames), i.e. a 10 second 120fps would end up being a 40 second video at 30fps.

Answer 1

Try using -r such as:

ffmpeg -y -r 30 -i inputSlowMotion.mp4 outputSlowMotion.mp4