Convert Matroska to WebM
We turn Matroska into WebM right in your browser — the file never goes to a server.
What you will lose
- Compression becomes lossy: the original quality cannot be restored
How they differ
| Matroska | WebM | |
|---|---|---|
| Lossless | yes | no |
| Lossy | yes | yes |
| Multichannel | yes | yes |
| Tags | yes | yes |
| Released | 2002 | 2010 |
| Author | CoreCodec |
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
WebM
Good at
- The browser’s own format: plays with no plugins at all
- Free of patent fees, which is why sites reach for it
- Noticeably lighter than older-style MP4 at the same quality
Awkward about
- Household devices and editing software barely know it
- On Apple hardware it plays only sometimes
- Audio is lossy only: Vorbis or Opus
Use it when
- The video goes on a web page and is watched in a browser
- You want the smallest file with the picture still alive
- A screen recording or a short clip for a page
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, WebM carries more than two channels — 5.1 stays 5.1.
- Can I get the original quality back afterwards?
- No. WebM is lossy, and the discarded detail cannot be recovered. Keep the original if you may still need it.
- How many files, and how large?
- Up to 3 files at a time, 500 MB each. No sign-up, no watermarks.