Drift GhostS .mp4 framerate conversion 59.9 to 25 - how?

[info]

Hello,
i do all my records and editing in 25fps at 1280×720 .mp4. Handed my Drift GhostS to a friend who "played" on it.
I did not notice he changed the videoformat, then did some records. Now I wanted to edit along with older footage and get
errors. Further examination revealed - the videos are 59.9 fps.
Is there a way to get 25fps material out what I have?
Any help apprciated.
regards
Jorgo

[LigH.de]

Imagine to slice an already sliced cake anew ... you won't be able to glue thin rest slices onto the other adjacent slice. That's the usual problem of video norm conversions. A second of time has already been split into one number of frames while recording. If the playback rate does not have a trivial ratio to it, all possible solutions will have negative side effects: a) speedup/slowdown will mess the audio; b) blending will create ghost images; c) motion compensated interpolation will occasionally fail with confusing artifacts.

[leghorn]

Also... Shouldn't 59.9 fps have smoother motion, and could therefore be preferred?

[LigH.de]

Some playback devices with lower integration may not handle such a Profile@Level easily. The thread starter might be forced to downsample. But exactly half the frame rate is less troublesome than a really different video norm. Modern HD playback devices should not have big issues with the frame rate range of 24/1.001 over 24.0, 25.0, and 30/1.001, to 30.0 fps.

[manono]

Why can't he go back to the original source, before his friend got his hands on it, and use that? And this is a German person with an NTSC 'source'. Downloaded or something? A sample would be nice so we can see what's been done and if it can be undone.

[LigH.de]

Drift Ghost S is an anction camera, up to FullHD. I would assume that it won't be possible to record the same scene again, after setting it back to a lower frame rate... And if you want to cut and arrange a whole movie out of several clips, the frame rate of all clips must match.

As already mentioned: Converting frame rates is possible, but every available method has side effects (like stuttering, a "soap opera effect", or playback speed changes).

[manono]

Oh, it's a camera. Now I understand. Thanks. I was under the mistaken impression he had lent a video to a friend who had reencoded it. Yes, unless he wants it to play jerky (by removing frames) or all ghosted (by blending frames), or artifact-ridden (by using frame interpolation to get it back to 25fps), he's in a bit of a bind, I think.

A short sample still might prove useful, to see what the best of the bad choices might be. For example, it might not be too bad to remove 2 out of every 3 frames to get it back to 20fps, followed by interpolating back to 25fps. Or maybe it'll look like crap.