Convert MKV to MP4 Online
Pick an MKV file and convert it to widely compatible MP4 on your device. Plays on any phone, tablet, smart TV, or computer.
How it works
- Upload your MKV file. Drag your MKV video into DomeScribe. Matroska files with H.264 video and AAC audio convert fastest; other codecs are re-encoded.
- Select MP4. Choose MP4 as the output. With resolution and frame rate left on "Original", DomeScribe repackages the existing streams into an MP4 container without re-encoding — quick and lossless when the codecs are MP4-compatible.
- Optionally downscale. Pick 1080p or 720p to shrink the output; DomeScribe then re-encodes the video as H.264 with AAC audio on your device.
- Convert and save. Click Convert and save the MP4 with a free account. It plays on smart TVs, game consoles, tablets, and any modern media player.
Converter at a glance
- Video formats
- MP4, MOV, AVI, WebM, MKV, FLV — optional resolution (4K to 360p) and frame rate (60/30/24 fps)
- Audio formats
- MP3, WAV, FLAC, AAC, OGG, M4A
- Privacy
- Runs 100% in your browser (WebAssembly) — your file is never uploaded to a server
- Speed
- No upload wait — processing starts as soon as the in-browser engine loads (~31 MB, cached after the first run)
- File size
- Limited by your device's memory — up to about 500 MB works reliably
- Watermark
- None
- Limits
- Free — no monthly limit; runs on your device (a free account is needed to save the file)
Frequently asked questions
Why do some devices not play MKV files?
The Matroska (MKV) container is flexible but not widely supported by consumer electronics. Most smart TVs, game consoles, and mobile devices are optimized for MP4. A DomeScribe conversion to MP4 ensures playback works on those devices without extra apps.
Can DomeScribe convert MKV to MP4 without re-encoding the video?
Yes. Leave resolution and frame rate on "Original" and DomeScribe repackages the existing streams into an MP4 container without re-encoding — quick and lossless when the MKV holds H.264/H.265 video with AAC audio.
What happens to subtitles in my MKV file during conversion?
Subtitle tracks are not carried over — the MP4 contains the video and the default audio track only. If you need subtitles, keep the original MKV or add them with a dedicated subtitle tool.
What if my MKV has several audio tracks?
DomeScribe keeps the default (first) audio track. Choosing a different track is not supported yet, so make sure the track you want is the default before converting.
My MKV has DTS or Dolby audio — will that work in MP4?
A plain remux may produce an MP4 that some players cannot decode, because MP4 players generally expect AAC. In that case pick a resolution (even the same as the source) so DomeScribe re-encodes the video as H.264 and the audio as AAC, which plays everywhere.
Related tools
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- Compress Video Online — Compress video files in your browser — typically 50–80% smaller with little visible quality loss. Free, no monthly limit, the video never leaves your device.