Convert MKV to MP4.
Make Matroska .mkv videos play everywhere as MP4, fast remux with ffmpeg, quality preserved.
MKV vs MP4
MKV (Matroska) is a flexible open container. It can hold almost any codec along with multiple audio and subtitle tracks, which is why movie rips so often use it. MP4 is the universal one that just plays: on phones, smart TVs, the web and in every video editor. Plenty of devices simply won't open an MKV, and converting fixes that.
Usually a fast, lossless remux
Most MKVs already hold H.264 or H.265 video, which MP4 also supports, so the streams are copied into a new MP4 container without re-encoding. That's quick and loses no quality. Only a codec MP4 can't carry would force a high-quality re-encode.
Watch the extra tracks
The one thing to know: MKV can bundle several audio languages and subtitle tracks, and MP4 handles fewer. Extra tracks may be dropped or need picking, and embedded subtitles in particular often don't carry across. Keep the MKV if those matter to you.
How it works
- 01
Add your MKV
Drop one or many files, or click to browse. Private by default.
- 02
Convert with a local engine
MKV becomes MP4 using a best-in-class open engine, no paid API in the loop.
- 03
Download
Grab your MP4 (or a zip of many), or open it in TranscriptAI to do more.
Best available engine, honest about limits
Private uploads, auto-deleted after 1 hour
Batch convert many at once, download as a zip
No watermark, no signup to try
Fast, faithful conversion
Direct handoff to TranscriptAI
MKV to MP4: transcode
MKV and MP4 are container/codec formats, so this re-encodes the video (a lossy step. Start from the best source you have). MP4 is broadly compatible, which helps when a player, editor or site won't accept MKV.
Your file is ready. Want to do more with it?
Open this file in TranscriptAI to generate a transcript, summary, structured notes, flashcards, quiz questions or action items: automatically.
Common questions
Is it free?+
Yes. Convert MKV to MP4 free, with no signup.
Is my file private?+
Uploads go to a private bucket, are converted, and auto-delete after 1 hour.
Will quality hold up?+
Remuxed without re-encoding where possible.
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