MKV compressor
Shrink an MKV (from OBS, a camera or a rip of your own disc) into a smaller MP4 that phones, chat apps and email accept.
What is a MKV file?
MKV (Matroska) is a flexible open container that can hold almost any video and audio codec plus subtitles and chapters. OBS can record to MKV because it survives crashes better.
Why MKV files get big, and how this shrinks them
Game recordings in MKV are often captured at very high bitrates to preserve detail. Re-encoding to a sharing bitrate shrinks them dramatically; trimming to the highlight helps most.
Tips for MKV
- Output is MP4 or WebM; subtitles and extra audio tracks are not carried over (the main video and audio track are).
- For OBS recordings, 1080p30 or 720p60 are good sharing targets.
- Very large MKVs are best handled on a computer because the browser holds the file in memory.
Need an exact size? Try 20 MB, 25 MB or the bitrate calculator.
Other formats
Questions people ask
Can I open MKV files in the browser?
Yes, Mediabunny reads Matroska. Whether a particular file decodes depends on the codec inside; H.264, HEVC, VP9 and AV1 MKVs usually work in Chrome and Edge.
Why does the output become MP4?
MP4 is accepted by far more apps and upload forms than MKV. Choose VP9 to get WebM instead.
Will I lose subtitles?
Yes, only the main video and audio tracks are kept. Burned-in subtitles stay, because they are part of the picture.