

I usually do everything from CLI.
Are you wanting to re-encode it to a different codec or just change the container from mkv to mp4?
To remux the file (change the container format), you can simply do:
# The -f mp4 is technically optional as it can deduce it from the extension, but I like to be explicit
ffmpeg -i file.mkv -f mp4 file.mp4
That should go very fast as it’s just copying the streams as-is into a new container.
If you want to re-encode it to a different codec, then you’ll need to use a more complex ffmpeg command.
















My takeaway is that I’m gonna start calling no-bake cookies “no bakies”.