Adjustable local compression
Compress MKV Video
Compress an MKV into a compatible H.264 MP4 at your chosen constant-quality level.
The FFmpeg engine downloads from a CDN once. Your media is not uploaded.
How to use the MKV video compressor
- STEP 1Choose a MKV video up to 200 MB.
- STEP 2Select the compression level from CRF 23 to 35.
- STEP 3Download the compressed MP4.
About this tool
Reduce delivery size with adjustable constant-quality H.264 encoding while producing a predictable modern MP4.
Higher CRF values generally reduce size by discarding more visual detail.
Resolution and frame rate remain unchanged; audio becomes 128 kbps AAC.
Frequently asked questions
How does the compression slider work?
CRF 23 prioritizes visual quality, while values closer to 35 create smaller files with more visible loss.
Will every result be smaller?
Usually, but not guaranteed. An already efficient source can occasionally produce a similar or larger output.
Which output format is used?
The result is H.264 MP4 with yuv420p video, 128 kbps AAC audio, and fast-start metadata.