Convert MTS to MP4
Convert MTS to MP4 online free: AVCHD camcorder clips become MP4 in seconds, the picture copied with no quality loss. Batch, no upload. No sign-up.
MTS
MTS (and M2TS) is the AVCHD format of Sony, Panasonic and Canon camcorders, stored on the card under PRIVATE/AVCHD/BDMV/STREAM.
The picture is H.264, which an MP4 holds as it is; the sound is usually Dolby Digital (AC-3) or PCM, which is re-encoded to AAC so phones and editors play it.
MTS to MP4: remux or re-encode
Converting MTS to MP4 is usually a remux: the H.264 or HEVC picture is copied as it is, so the result looks exactly like the original. Sound that MP4 players don’t take (AC-3, PCM) is re-encoded on its own, which takes seconds.
A remuxed file is about the same size as the MTS. A re-encode, or the High, Balanced and Small presets, makes it smaller: a 1080p minute is around 45 MB at High and 30 MB at Balanced.
How it works
- Drop one or more MTS files: MP4 is already selected. Quality, maximum resolution and sound can be changed before you start.
- Streams that fit MP4 are copied; anything else is re-encoded with WebCodecs, or FFmpeg compiled to WebAssembly when the browser can’t.
- Download each file, or all of them as one ZIP.
Questions
Which file do I take from the camcorder card?
The MTS files under PRIVATE/AVCHD/BDMV/STREAM. A long recording can be split into several MTS files; convert them all and join them with Merge Videos.
Are my videos uploaded?
No. Reading, remuxing and encoding all run in this browser tab. Open DevTools and watch the Network tab while a file converts: no request carries it.
Why is one file done in seconds and another takes minutes?
A remux only copies the streams, so it runs at disk speed. A re-encode decodes and encodes every frame; FFmpeg in WebAssembly, used when the browser can’t, is slower still.
How large can a video be?
Up to 3 GB per file for free, and as many files as you like. Remuxes and WebCodecs re-encodes stream from the disk; the FFmpeg path holds the result in memory.