About MKV to MP4
MKV files from downloads or OBS often will not play on iPhones, TVs, or in editors. MP4 plays nearly everywhere.
If the MKV already holds H.264 video, it is copied into MP4 without re-encoding — fast and lossless. HEVC or VP9 video is re-encoded to H.264, which takes longer. Only the first video and audio track are kept; subtitles are not carried over.
The FFmpeg engine (about 31 MB) downloads the first time you convert and is then cached by your browser. Files up to about 100 MB are supported because everything runs in browser memory.
MKV vs MP4
| MKV | MP4 | |
|---|---|---|
| What it is | Matroska container | MPEG-4 Part 14 container |
| Typical codecs | Often H.264 or HEVC video with AAC, AC-3, or Opus audio | H.264 or HEVC video, AAC audio |
| Common use | Downloads, recordings (OBS), subtitles and multiple tracks | Plays almost everywhere |
How to do it
- 1
Drop a MKV file into the converter above (already set to MP4).
- 2
No settings needed.
- 3
Tap Convert, keep the tab open until it finishes, then download the MP4.