Convert MKV to MP4
Settings
No file yet
Settings appear after you choose a file.
OBS and other screen recorders save MKV, which many editors and players will not open. The MP4 holds the same video in the container they expect.
MKV or MP4?
Keep MKV when
- It is the original. The encode lines make a lossy copy; only the copy line keeps every detail.
Pick MP4 when
- A program, a site or a device asks for MP4 files.
About MKV and MP4
MKV
A flexible video container that holds several audio tracks and subtitles in one file. Popular for films and screen captures.
MP4
The most widely used video format. It plays on most phones, computers and platforms, and is the usual way video is shared.
Questions
Does the MP4 look worse?
Not with the copy line, which keeps the picture and the sound exactly. The encode lines and the HandBrake and VLC routes encode again, so they drop a little detail; a lower CRF loses less.
What does the copy line do?
It moves the picture and the sound into the MP4 as they are, without encoding them again, so nothing is lost and it takes seconds. It works when the MKV holds H.264 video and AAC sound, the pair an MP4 takes; for any other codec use the first line. -c copy means that.
Which CRF should I pick?
The commands use CRF 23, a common middle ground between size and quality. Change -crf 23 to a lower number for a better picture and a larger file, or a higher one for a smaller file, 0 to 51.
Are the MKV's subtitles kept?
Not by the Terminal lines: they keep the picture and one sound track, and leave subtitles and any other sound tracks out.
Can I convert a whole folder at once?
Yes. Drop them all here. In Terminal, one line converts every MKV in the folder.