MP4 to MKV Converter
Repackage MP4 video into the flexible MKV (Matroska) container.
MKV (Matroska) is an open, flexible container that can hold multiple video, audio, and subtitle tracks in a single file — a favorite for media servers and archiving. Converting your MP4 to MKV gives you that flexibility.
When the video codec is already compatible, the stream can be copied without re-encoding, so the conversion is fast and keeps the original quality. It all runs in your browser.
How to convert MP4 to MKV
- 1Drop your MP4 file into the area above — or click to browse.
- 2The output format is already set to MKV. Adjust the quality settings if the format supports them.
- 3Click convert, then download your MKV file. Everything runs locally — nothing is uploaded.
Frequently asked questions
Often not at all. If the existing codec is supported, the video stream is copied straight into the MKV container with no re-encoding, preserving the original quality exactly.
MKV can bundle multiple audio tracks and subtitles, and it's the preferred container for many home media servers and archival setups. MP4 is simpler but less flexible.
No. All processing happens entirely in your browser. Your data never leaves your device — nothing is uploaded to any server.
Yes. Once the page has loaded, the tool works completely offline. For the best experience, install PrivaDeck as a PWA from your browser.
Other conversions
Need a different format?
Open the full video converter to switch between MP4, MKV and AVI, choose H.264 or H.265, and convert with hardware acceleration where available.
Open the full Video Converter