MKV file format (.mkv)
Matroska container. Holds anything, and is ideal for archiving.
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What is an MKV file?
In short: An MKV file (.mkv) is a video file in the MKV format. Matroska will hold essentially any combination of video, audio and subtitle streams, in any codec, in unlimited numbers, with chapters and attachments alongside. It can be converted to MP4, MOV or GIF for free in a web browser with iHateFiles, without uploading it.
Started in 2002 as an open alternative to the proprietary containers of the time.
Matroska will hold essentially any combination of video, audio and subtitle streams, in any codec, in unlimited numbers, with chapters and attachments alongside. That is why it is the format of choice for archived films with several language tracks and subtitle sets.
What MKV is good at
- Any codec, any number of tracks
- Proper chapters, subtitles and attachments
- Open specification with no licensing
Where MKV falls short
- Browsers do not play it
- Support on TVs and phones is inconsistent
- A file can contain codecs the player has never seen
When to use MKV
Use MKV for archiving video where you want every track kept. Convert to MP4 for playback on anything other than a computer.
How to open a MKV file
VLC, MPV and most desktop players. Not browsers, and not reliably on TVs.
| Windows | VLC or MPC-HC. Windows Media Player has never supported Matroska; the Films & TV app will open some MKVs and refuse others depending on the codecs inside. |
|---|---|
| macOS | IINA or VLC. QuickTime will not open it at all, which is the usual reason people arrive looking for a converter. |
| Linux | VLC, mpv and Totem all handle it. Matroska is the default container for most Linux recording tools. |
| Phone | VLC or MX Player on Android. On iOS, VLC — the built-in player will not take it. |
| In a browser | No browser plays MKV. Chrome will sometimes play one renamed to .webm if the codecs happen to be VP8 or VP9. |
The thing that usually goes wrong
MKV and WEBM share a signature because WEBM is a restricted Matroska, so tools sometimes report one as the other. What matters is the codecs inside.
Questions
What is a MKV file?
Matroska container. Holds anything, and is ideal for archiving. Files use the .mkv extension.
How do I open a MKV file?
Most video software opens MKV directly. If yours does not, convert it here to something more common. It takes a few seconds and nothing is uploaded.
Can I convert MKV for free?
Yes. Every conversion here is free and unlimited, because your own device does the work rather than a server we have to pay for.
Is MKV lossless?
That depends on the codec inside the container rather than the container itself. Everything written here is re-encoded, so expect one generation of loss.