.mkvWhat is MKV?
Matroska Video
The flexible archival container — any codec, multiple tracks
- Container standard
- Matroska (EBML-based)
- Supported video codecs
- H.264, H.265, VP9, AV1, and more
- Supported audio codecs
- Any — AAC, AC3, DTS, FLAC, Opus, etc.
- File extension
- .mkv
MKV (Matroska Video) is an open, free container format that can hold virtually any combination of video, audio, and subtitle streams in a single file. Unlike MP4 or AVI, Matroska imposes no restrictions on which codecs can be used inside the container — H.264, H.265, VP9, AV1, and dozens of other codecs are all valid. This flexibility makes MKV the preferred format for high-quality video archival, multi-language content, and downloaded movies.
MKV files commonly contain multiple audio tracks (e.g. English and Spanish dubbing), multiple subtitle streams, and chapter markers — features that MP4 supports only partially. The format is popular in the anime and home theatre communities, where preserving all original tracks from a source disc is important. For wide distribution or editing, MKV content is typically remuxed or transcoded to MP4.
Technical Specifications
| Container standard | Matroska (EBML-based) |
| Supported video codecs | H.264, H.265, VP9, AV1, and more |
| Supported audio codecs | Any — AAC, AC3, DTS, FLAC, Opus, etc. |
| File extension | .mkv |
| MIME type | video/x-matroska |
| Subtitle support | SRT, ASS, PGS, and more — embedded |
| Chapters | Yes — Blu-ray-style chapter navigation |
Advantages & Limitations
Advantages
- Accepts any video and audio codec — no restrictions
- Supports multiple audio tracks for multi-language content
- Embeds subtitle streams (SRT, ASS, PGS) directly
- Supports chapter markers and navigation metadata
- Ideal for lossless remux from Blu-ray without re-encoding
- Open and free — no licensing fees
Limitations
- Not natively supported on iOS or most Android devices
- Social media platforms reject MKV uploads
- Not supported by all video editors without conversion
- Larger file sizes than equivalent MP4 for the same codec
Common Use Cases
- Long-term video archival and storage
- Blu-ray and DVD remuxing without quality loss
- Multi-language content with multiple audio tracks
- Anime and foreign film collections with subtitles
- Media server libraries (Plex, Jellyfin, Kodi)
- Home theatre PC playback
Compatible Software & Platforms
MKV is natively supported by:
Convert MKV Files — Free Online Tools
Convert from MKV
Convert to MKV
Frequently Asked Questions
What is a MKV file?
A MKV file is a video file using the Matroska Video format. MKV (Matroska Video) is an open, free container format that can hold virtually any combination of video, audio, and subtitle streams in a single file.
What programs open MKV files?
MKV files are supported by: VLC, MPV, Kodi, Plex, Jellyfin, and most modern media players and editors.
What are MKV files used for?
Common uses include: Long-term video archival and storage; Blu-ray and DVD remuxing without quality loss; Multi-language content with multiple audio tracks.
MKV vs MP4: what is the difference?
MKV supports more tracks and codecs; MP4 has better device and platform compatibility. MKV is typically chosen for long-term video archival and storage, while MP4 is preferred for uploading to youtube, tiktok, instagram, and vimeo.
How do I convert a MKV file?
Convert MKV files online for free at MediaFormatter. Upload your file, choose a target format, and download the result — no installation or sign-up needed.