MKV file format
Matroska Video
MKV (Matroska) is an open, flexible container that can hold almost any codec plus unlimited audio and subtitle tracks. It's popular for movies and archives, but many phones and editors can't open it.
| Property | MKV |
|---|---|
| File extensions | .mkv |
| MIME type | video/x-matroska |
| Introduced | 2002 by Matroska project (open standard) |
| Typical video codecs | Any: H.264, HEVC, VP9, AV1… |
| Typical audio codecs | Any: AAC, Opus, FLAC, DTS, AC-3… |
| Plays in web browsers | Partly (Chrome/Edge for some codecs) |
| Compatibility | VLC, Plex, Kodi, most smart TVs; not iPhone or many editors |
| Best for | Movies with multiple audio and subtitle tracks |
What is an MKV file?
MKV is the Matroska container, an open standard first released in 2002. It can hold virtually any video, audio or subtitle codec, and any number of tracks — so one file can carry several languages, director's commentary and subtitles. WebM is a restricted subset of Matroska.
Strengths and weaknesses
MKV is ideal for archiving: it's robust against damage, supports chapters and attachments, and never forces a re-encode. But iPhones, many Android galleries, Premiere Pro and most social networks don't accept MKV.
When should you use MKV?
Use MKV to store movies with multiple tracks or to archive without quality loss. Convert to MP4 for phones, editing and uploads — usually a fast repackage, since most MKVs contain H.264 video.