Does increasing fps 30-->60 when (ffmpeg) re-econding repair stuttering?

[pxstein]

I have a (smartphone) video which was originally recorded with 30fps.

Sometimes scenes are stuttering a little.

So when I re-encode these videos (with the same codec H.264) but increase the fps up to 60 does this help to repair stuttering?

In order words: does ffmpeg really calculate the additional new frames as intermediate half-way steps between the two existing frames?
Or are are the new frames more or less just added as stupid dummy frames?

[poisondeathray]

I have a (smartphone) video which was originally recorded with 30fps.

Sometimes scenes are stuttering a little.

So when I re-encode these videos (with the same codec H.264) but increase the fps up to 60 does this help to repair stuttering?

In order words: does ffmpeg really calculate the additional new frames as intermediate half-way steps between the two existing frames?
Or are are the new frames more or less just added as stupid dummy frames?

Normally the new added frames are just duplicate frames ( or sometimes effectively duplicates from timestamp changes), unless you use something like -vf minterpolate (but it has some bugs and memory leak)
https://ffmpeg.org/ffmpeg-filters.html#minterpolate

However , smartphone videos are usually VFR (variable frame rate) . 30 FPS isn't really 30FPS . There are sections where the fps will drop - those sections will stutter.

You can check with mediainfo (view=>text) it will usually report a min and max framerate, or -vf vfrdet in ffmpeg
https://ffmpeg.org/ffmpeg-filters.html#vfrdet