Changing mkv container to mp4 without frame drops???

[loganm187]

I recently got a job cutting trailers for an indie theater and most of my sources are bluray which I take an mkv file from and then use box 4 or shanaencoder to change them to mp4 so I can edit them in davinci resolve.

The issue is when I change the container to mp4 I get random dropped frames throughout the file. How is this happening when just changing containers? It happens exactly the same across any movie, any player, and both container switching apps I listed above. I do not want to compress these files or spend hours in handbrake. Switching containers is quick with these programs, but something is wrong. Is there a better program to do this with? Is there a makemkv like app that just puts the untouched contents into an mp4 file?

This is driving me mad. Any help would be awesome. Editing around frame drops to make trailers is annoying.

[Woodstock]

JUST changing containers should not be an issue, assuming that the video, audio, and subtitle codecs are all MP4-compatible. There are several tools out there that will "remux" the tracks into an MP4, without changing the tracks. Searching internet for "remux mkv to mp4" comes up with a number of alternatives.

If the codecs are NOT MP4-compatible, though, you get into encoders, which can drop frames, as you're seeing. I have not had this issue with handbrake, but it is re-encoding the video. Your application would seem to not require that.

In which case, ffmpeg might be the fix for you. It is command-line driven, and you can tell it just which tracks to pass through untouched, and which ones to re-encode to fix compatibility with MP4.

Question - is the playback environment incapable of handling MKV files?

[loganm187]

We play almost exclusively MKV files, but not a single NLE program will edit an mkv hence my need to change containers to mp4 which can then be edited. I tried ffmpeg awhile back with the same results. This is baffling....I'm just switching containers!!

[Woodstock]

Found this page with a simple search, which includes doing it with ffmpeg: https://www.anymp4.com/converter/remux-mkv-to-mp4.html