Download your converted MP4 to MKV file here when ready.
Hold tight, processing may take a minute...
Download your converted MP4 to MKV file here when ready.
Step 1: Add a video: drag & drop an MP4 or paste a URL.
Step 2: Click Convert to MKV: the tool will remux when compatible (fast, no quality loss) or transcode if needed for compatibility.
Step 3: Preview & download: check playback, then save the .mkv file to your device.
Works on Windows, macOS, Linux, and mobile browsers.
Matroska (MKV) = flexible container: supports multiple audio tracks, soft subtitles, chapters, and a variety of codecs.
MP4 = widest device support: best for built-in players and some social networks.
If you need extra tracks or subs, MKV often fits better. For maximum compatibility, MP4 may still be preferable.
Files are processed securely and deleted after conversion. Free demo supports smaller files but you can sign up to increase limits and unlock batch processing.
The open-source code for this project is available on GitHub, offering a starting point for those interested in building their own media conversion tools or video editing application.
If you need to run MP4 to MKV at scale—batch jobs, user uploads, CI/CD steps — Shotstack's Video Editing API turns this demo into a repeatable pipeline with templates, queues, retries, webhooks, and global delivery via the Serve API.
curl --request POST 'https://api.shotstack.io/v1/render' \
--header 'x-api-key: YOUR_API_KEY' \
--data-raw '{
"timeline": {
"tracks": [
{
"clips": [
{
"asset": {
"type": "video",
"src": "https://shotstack-assets.s3.amazonaws.com/footage/beach-overhead.mp4"
},
"start": 0,
"length": "auto"
}
]
}
]
},
"output": {
"format": "mp4",
"size": {
"width": 1280,
"height": 720
}
}
}'