MP4 to MKV
Drop an MP4 from almost every phone, camera app and editor export and get an MKV file you can use where MP4 won't open.
Your file stays on your device. Nothing is uploaded.
MP4 to MKV in three steps
Drop your MP4
Up to 500 MB.
Convert
The video is copied into a new file when it can be, which is fast.
Download the MKV
Ready to play, edit or upload.
MP4 vs MKV, in short
MP4 is the most widely supported video format: phones, browsers, editors and every upload site play it.
MKV (Matroska) is a flexible container that can hold several audio and subtitle tracks. OBS and other recorders use it because a recording survives a crash, but phones and many editors don't open it.
MP4 and MKV can hold the same kinds of video, so the tool first tries copying the video and sound into the new file without re-encoding. That takes seconds and keeps the exact quality. If the codecs don't fit, it re-encodes to H.264 video with AAC sound.
Frequently
Asked Questions
Does converting MP4 to MKV lose quality?
Usually not: when the codecs fit, the video is copied as-is. Otherwise it's re-encoded once, which most people won't notice.
Is the sound kept?
Yes. The audio track comes along with the video.
How long does it take?
Seconds for most files, when the video can be copied. Re-encoding takes longer: a few minutes for a few minutes of video.
Is my file uploaded?
No. It's processed in your browser, on your own device, and never leaves it.