The MKV to MP4 Converter handles mkv to mp4 inside your browser tab. Drop a recording from OBS or a file you downloaded, and get an MP4 that plays on phones, TVs, Windows apps and video editors. Nothing is uploaded or stored, and it spends no credits.
Why convert MKV to MP4?
MKV, short for Matroska, is a flexible container. It can hold several audio tracks, subtitle tracks and chapters in one file, which is why OBS offers it as a safe recording format and why many downloaded videos use it. That flexibility comes at a price: plenty of players, phones, editors and upload forms don’t accept it.
MP4 is the format they do accept. Converting MKV to MP4 turns a recording that only opens in a few players into a file you can drop into an editor, send to a phone or post on a social platform.
Does MKV to MP4 lose quality?
Not when the codecs already fit. An OBS recording usually holds H.264 video and AAC audio, and MP4 takes both. The converter then copies the streams into the new container without re-encoding, which is quick and keeps every frame as it was.
If the MKV uses a codec MP4 can’t hold, the converter re-encodes it at a balanced quality. That is slower and lossy, as every re-encode is. Whether a less common codec can be read at all depends on your browser.
What happens to extra audio and subtitle tracks?
MKV files can carry more than MP4 is built for. Treat the MP4 as a file for playing and sharing: if you need every track, subtitle and chapter from the original, keep the MKV as your archive copy.
How to convert MKV to MP4
- Drop the MKV file or pick it from your device.
- MP4 is preselected, so start the conversion.
- Follow the progress bar and download the MP4. The Stop button cancels at any point.
It needs a recent Chrome, Edge or Firefox, or Safari 17 and later. Long recordings are kept in memory while they convert, so very large files depend on your device. For a lighter file after converting, use Compress Video.
FAQ
Can I remux OBS recordings with this?
Yes. When the recording holds H.264 and AAC, the converter copies the streams into an MP4 without re-encoding, which is what remuxing means.
Is the video sent to a server?
No. The mkv to mp4 conversion runs on your device, and nothing is stored.
What does it cost?
It comes with the Nexin library: Nexin Lite or Nexin Pro opens it, and it spends no credits.
