MKV to MP4 your OBS recording, ready to edit.
To convert MKV to MP4, choose your OBS recording or any other .mkv file and click convert. OBS recordings usually hold H.264, HEVC or AV1 video with AAC audio, so we only swap the container: the MP4 comes out in seconds, with no quality loss and every audio track intact.
Free, no sign-upEverything fits MP4: we only swap the container. It takes seconds and the quality stays identical.
This video is HDR. When it is re-encoded, colors may look different from the original.
For Windows PCs without the HEVC extension, older TVs and iPhones or Macs without AV1. Takes longer.
How to turn an MKV into an MP4
- 01
Choose the .mkv
Drag the recording onto the area above or pick it from your computer. OBS saves to your Videos folder unless you changed the path in the output settings.
- 02
Check the plan
For OBS recordings the plan usually says copied without re-encoding, for the video and for each audio track. If anything is re-encoded, we show why.
- 03
Download the MP4
The copy is fast, even for streams that ran for hours. Watch the preview, check the report and download the .mp4 with the same name as the .mkv.
Why does OBS record in MKV?
A regular MP4 is only complete at the end of the recording, when the frame index is written. If OBS crashes, the power goes out or the disk fills up before that, the whole MP4 becomes unreadable. MKV stores video in independent blocks and still opens up to the last second recorded. That's why OBS recommended MKV for years.
Starting with version 30.2, OBS offers Hybrid MP4, which survives crashes and opens like an MP4. Even so, plenty of people still record MKV out of habit or old settings. OBS itself has a remux option in the File menu and another to convert to MP4 automatically after each recording. This page does the same container swap without opening OBS.
| What's inside the MKV | What we do | Time |
|---|---|---|
| H.264 + AAC (OBS default) | Copy into MP4 | Seconds |
| HEVC or AV1 + AAC | Copy into MP4 | Seconds |
| Opus audio | Audio becomes AAC | Fast |
| VP8 or VP9 | Re-encode to H.264 | Minutes |
| AC-3 or DTS | Copy as is | Seconds |
| Embedded subtitles | Not carried into the MP4 | - |
MKV with several audio tracks: what happens?
OBS records up to six separate audio tracks, a common setup for streams: the mic on one track, the game on another, music on a third. Every track goes into the MP4 exactly as it was. In your editor each one shows up separately, so you can set the volume of each source freely. A regular player plays only the first.
MKV files from other sources, such as downloads, can bring other formats. AC-3 and DTS go into the MP4 as they are, and some players and browsers don't play that audio. If an audio track can't be read or copied, the file comes out without it, and the report says so. Subtitles embedded in the MKV are not carried into the MP4; if you need them, keep the SRT separately.
Editors that won't open MKV
Final Cut Pro doesn't import MKV. Premiere Pro only started opening MKV with H.264 in its 2025 versions, and MKV with HEVC is still rejected. DaVinci Resolve opens MKV, but AC-3 audio often comes in silent. Phones, QuickTime and WhatsApp don't handle MKV well either. With MP4, those problems go away.
Because the copy recompresses nothing, the recording reaches your editor with the same picture, the same sound and the same length. If it was recorded in HEVC or AV1 and is going to an older computer, tick maximum compatibility to get H.264.
- Streams that ran for hours convert quickly, because nothing is recompressed.
- A 60 fps recording stays at 60 fps: the frame rate does not change.
- The file name stays the same; only the extension changes to .mp4.
More than MKV to MP4. Your stream becomes clips, text and chapters.
See also
Frequently asked questions
How do I convert MKV to MP4 for free?
Choose the .mkv file on this page and click convert MKV to MP4. For OBS recordings we copy the video and audio without recompressing, and the MP4 is ready in seconds. It's free, with no sign-up, no watermark and no usage limit.
Does converting MKV to MP4 lose quality?
No, when the MKV holds H.264, HEVC or AV1 with AAC, as OBS recordings do. We only swap the container and the picture stays identical. Recompression only happens with VP8 or VP9, with Opus audio, or if you tick maximum compatibility.
What's the difference between MKV and MP4?
Both are containers for the same kind of video. MKV survives crashes and accepts almost any codec and subtitle, but little outside a computer opens it. MP4 plays on phones, editors, TVs and social networks, but a regular MP4 interrupted mid-recording becomes unreadable.
Are OBS's multiple audio tracks kept?
Yes. Every audio track goes into the MP4, separate just like in the MKV. In your editor each track shows up on its own, and a regular player plays the first.
Should I record MKV or MP4 in OBS?
If your OBS version has Hybrid MP4, it gives you the best of both: it survives crashes and opens like an MP4. On older versions, record MKV and convert afterwards, here or with OBS's own remux. Recording straight to regular MP4 risks losing the whole recording in a crash.
My downloaded MKV lost its audio. Why?
Some MKV files carry audio in formats we can't read or copy into MP4. In that case the file comes out without that track, and the report says which audio was left out. AC-3 and DTS are copied, but not every player plays them.
Turn the whole stream into clips. We find the best moments.
Upload the recording or paste a YouTube link. We transcribe it, split it by topic and deliver 4 to 60 vertical captioned clips, ready to review and download.
See the result on your own recording before adding a card.