Convert MKV to MP4
Most MKVs already contain MP4-compatible video (H.264/HEVC) — those convert instantly, bit-identical, even at 4 GB+.
- Instant remux for H.264/HEVC/AV1 MKVs
- MKVs with AC-3 audio: video kept, audio needs a re-encode (AAC)
- No upload — files never leave your device
- No watermark, no size cap
Frequently asked questions
Why do other tools take an hour on my 4 GB MKV?
They upload it, queue it and re-encode everything. When your MKV's video is H.264/HEVC/AV1 (the overwhelming majority), the packets go straight into an MP4 container at disk speed — typically well under a minute for 4 GB.
My MKV has AC-3 / DTS audio — what happens?
MP4 players rarely accept AC-3, and browsers can't decode DTS at all. Where the audio can be decoded it's re-encoded to AAC; where it can't, you get an honest message naming the codec instead of a silent video.
Multiple audio tracks / subtitles?
v1 keeps the primary audio track and drops soft subtitles (MP4 subtitle support is a mess across players). The probe lists every track it found so you know before converting.