[FFmpeg-user] slow motion by changing frame rate from 60 to 30

[Michael Koch]

Am 01.10.2020 um 16:57 schrieb Cristian Secară:
> I want to make a short .mp4 clip filmed in 1080p/60 format, then change somehow the playing fame rate to 30Hz so that the playing speed becomes twice slower. Audio is not important (may be dropped completely).
>
> As far as I know (?), a "simple" frame rate change will try to preserve the playing speed, so when changing from 60Hz to 30Hz, it will drop half of the movie.
> At the same time, a "simple" slow motion processing will try to keep the original frame rate, so in this case it will interpolate the transitions or something, while keeping the frame rate still at 60Hz.
>
> What options are available for preserving all frames "as is" and just slowing down the playing speed ?

It's described here:
https://trac.ffmpeg.org/wiki/How%20to%20speed%20up%20/%20slow%20down%20a%20video

Michael