MKV to MP4
Repackage an MKV video as MP4 so more players and apps open it. Nothing is uploaded.
Drop MKV files here
Converted on your device. Files are never uploaded.
Up to 20 files at a time.
MKV holds almost any mix of video, audio and subtitles, but TVs, phones, editors and upload forms often want MP4 instead. FormatJet copies the video and audio from your MKV into an MP4 container, re-encoding only what MP4 can’t hold as it is. It runs in your browser, so the video stays on your device.
About the formats
MKVMatroska video
MKV (Matroska) is an open video container that can hold several audio and subtitle tracks. Media players like VLC open it, but phones, editors and TVs often don’t.
MP4MP4 video
MP4 is the most widely supported video format, used by phones, cameras and websites. It usually holds H.264 or HEVC video with AAC audio.
Converted with Mediabunny, Media engine (FFmpeg).
Questions
Are subtitles in the MKV kept?
No. Subtitle tracks inside an MKV aren’t carried over to the MP4. Hold on to the MKV, or to a separate subtitle file, if you need them.
Does MKV to MP4 reduce the video quality?
Not when the streams can go into MP4 as they are; then the video and audio are copied across untouched. A stream MP4 can’t carry unchanged is re-encoded in your browser, which costs time and some quality.
Can I convert a full-length film?
Yes, up to 1 GB. The MKV is read piece by piece rather than loaded whole, and copying streams avoids compressing every frame again.
Does the MP4 keep the video’s tags?
Tags Mediabunny can read from the MKV, such as the artist, are written into the MP4, so players show the same details.
Will it work in my browser?
Copying the streams needs no video decoder, so any browser that runs FormatJet can do it.
MKV to MP4 with the API
The conversion API opens later this year.
curl https://api.formatjet.com/v1/convert?to=mp4 \
-H "Authorization: Bearer fj_test_…" \
-F file=@input.mkv -o output.mp4