.mkv — Matroska Video
A flexible open video container often used for high-quality movies, subtitles, and multiple audio tracks.
About this format
MKV is a container, not a codec. It can hold video, audio, subtitles, chapters, attachments, and metadata in one file.
Use MKV when you need a rich local media container. Convert to MP4 or WebM when you need broad browser or platform upload support.
Real-world samples & file sizes
MKV samples should be judged in the sizes people actually receive, upload, or export. These reference cards show the common shapes and settings to check before choosing a conversion target.
landscape video
The baseline export for web players and presentations.
vertical video
Used by stories, reels, shorts, and phone captures.
square post
Useful where feeds crop landscape video too aggressively.
portrait feed
A feed-friendly alternative to full vertical video.
Reference dimensions are platform-style targets. Compatibility and format facts are verified from the linked online sources below.
Pros
- +Supports many codecs and subtitle tracks
- +Good for local libraries and archival video
- +Open container design
Cons
- −Not accepted by many web upload forms
- −Browser playback is limited
- −Compatibility depends on the codecs inside
MKV vs other formats
| vs | Size | Quality | Note |
|---|---|---|---|
| MP4 | Similar with same codec | Container does not set quality | MP4 wins on device and browser compatibility. |
| WebM | Similar with same bitrate | Depends on codec | WebM is more web-focused; MKV is more flexible. |
Where it works
- Windows with Movies & TV or codecs
- macOS via VLC/IINA
- Linux media players
- Limited direct browser support
- Chrome may play some codec combinations
- Safari support is poor
- VLC
- IINA
- mpv
- Plex
- HandBrake
Related tools
Frequently asked questions
- Why will one MKV play and another fail?
- MKV is only the container. Playback also depends on the video and audio codecs stored inside it.
- Is MKV good for websites?
- Usually no. Convert to MP4 or WebM for web delivery.
Sources
- Matroska official documentation - Matroska container design and technical notes
- Library of Congress file format descriptions - archival format descriptions and sustainability notes
Other video formats
- .webm WebMGoogle's open, royalty-free video format for the web — typically 30-50% smaller than equivalent MP4 / H.264.
- .mov MOVApple's QuickTime movie container, common in camera exports, editing apps, and macOS workflows.
- .avi AVIAn older Windows video container that still appears in legacy cameras, screen recorders, and archives.