Matroska 1-4
Writablevideo
The Matroska Multimedia Container is an open standard free container format, based on the Extensible Binary Meta Language (EBML). Matroska file extensions are .MKV for video (with subtitles and audio), .MK3D for stereoscopic video, .MKA for audio-only files, and .MKS for subtitles only. The Internet Engineering Task Force (IETF) Working Group: Codec Encoding for LossLess Archiving and Realtime transmission (cellar) is tasked with the standardisation of Matroska. The EBML specifications are work-in-progress, and can be found here: https://github.com/Matroska-Org/ebml-specification/blob/master/specification.markdown
Identify it
| Extensions | .mkv.mk3d.mka.mks |
|---|---|
| PRONOM | fmt/569 |
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Open it
- FFmpegOpen source
Convert it
| To | With | Fidelity | Command and losses |
|---|---|---|---|
| FLAC (Free Lossless Audio Codec) 1.2.1 | FFmpeg | Partial | ffmpeg -i in.mkv out.flacAudio track only: the video is dropped. |
| Waveform Audio | FFmpeg | Partial | ffmpeg -i in.mkv out.wavAudio track only: the video is dropped. |
| MPEG 1/2 Audio Layer 3 | FFmpeg | Lossy | ffmpeg -i in.mkv out.mp3Lossy audio only: the video is dropped. |
| MPEG-4 Part 14 | FFmpeg | Lossy | ffmpeg -i in.mkv out.mp4Re-encoded with lossy codecs by default; try `-c copy` to remux without re-encoding when the codecs fit the container. |
| Ogg | FFmpeg | Lossy | ffmpeg -i in.mkv out.oggLossy audio only: the video is dropped. |
| WebM | FFmpeg | Lossy | ffmpeg -i in.mkv out.webmRe-encoded with lossy codecs by default; try `-c copy` to remux without re-encoding when the codecs fit the container. |
Sources
From Converters (FFmpeg, ImageMagick, Pandoc, LibreOffice), PRONOM. Updated 2026-10-20.