How to convert video from variable frame rate to constant?

Question

Video

Good afternoon!
I ran into a problem - I'm editing a video shot on an iphone, but after rendering in premiere, the video turns out to be out of sync and "lags" (every 2-3 minutes frames of the beginning of the video appear, and so the whole timeline).
As I was able to find out, the problem may be in the variable frame rate in the source, shot on the iphone.
Perhaps someone faced a similar problem.
Can you please tell me the best way to equalize the frame rate in an iphone video (filmed in 1080p60)?

Answer 1

Try the free VirtualDub2 https://sourceforge.net/projects/vdfiltermod/
File - Open
Video - Ftame Rate - Change frame rate to fps (specify the desired frequency)
Video - Compression - X164 (or Lagarith codec, but the file size will increase 10 times , though details will be preserved for comfortable work in the premiere)
Audio - Full processing mode
File - Save video - file type - MOV

Answer 2

You can change the frame rate (fps) quickly without transcoding using the HandBrake program. The only disadvantage of this method is that the number of frames increases due to the insertion of intermediate duplicate frames.
But if you need very good quality at high conversion speed, then there is such a way to increase the number of frames to any value with the creation of intermediate frames by interpolation, which increases the smoothness of the video: InterFrame2 script for AviSynth.
Here is a detailed instruction: https://www.spirton.com/convert-videos-to-60fps/ in English, but with pictures.