Convert MP4 to Matroska
We turn MP4 into Matroska right in your browser — the file never goes to a server.
What you will lose
Nothing to lose, and nothing to gain: {to} keeps exactly what {from} hands over, and the file grows several times over.
How they differ
| MP4 | Matroska | |
|---|---|---|
| Lossless | no | yes |
| Lossy | yes | yes |
| Multichannel | yes | yes |
| Tags | yes | yes |
| Released | 2001 | 2002 |
| Author | MPEG | CoreCodec |
MP4
Good at
- Plays on everything: TVs, car stereos, phones a decade old
- Carries several audio tracks, subtitles and chapters in one file
- Streams well: playback starts before the file has finished loading
Awkward about
- Anything can be inside — the extension does not tell you if it will play
- The audio is almost always lossy, so it is not a master copy
- Editing without re-encoding is close to impossible in this container
Use it when
- The video is being sent or published and has to open for everyone
- Footage from a phone that people will simply watch
- One audio track is all you need
Matroska
Good at
- Takes anything inside: any codec, a dozen tracks, subtitle fonts
- The one common container people fill with lossless audio
- Tracks and subtitles can be swapped without touching the picture
Awkward about
- TVs and phones often refuse to open it
- No browser plays it directly
- Files run larger: what goes inside is usually less compressed
Use it when
- A home archive where everything should be kept as it was
- Several audio languages and subtitle tracks in one file
- The file is watched on a computer, not on household hardware
Common questions
- Does the file get uploaded to a server?
- Yes, this pair needs the server: browsers cannot encode that format. The file and the result are deleted within a couple of hours and never shared.
- Will surround sound survive?
- Yes, Matroska carries more than two channels — 5.1 stays 5.1.
- Can I get the original quality back afterwards?
- Nothing is lost, but nothing is gained either. Matroska stores exactly what MP4 hands over, including the gaps MP4 left behind when it compressed. No tool can bring those back, and the file grows several times over. This conversion makes sense for editing, not for quality.
- How many files, and how large?
- Up to 3 files at a time, 500 MB each. No sign-up, no watermarks.