MTS (or M2TS) is the container AVCHD camcorders write to SD cards. Inside is H.264 video and AC-3 or Dolby audio. It plays in VLC but most editors, web players, and phones refuse it.

Can I convert MTS to MP4 without re-encoding?

Yes, if the audio is AAC. Most AVCHD audio is AC-3 which MP4 can also hold, so it's often a pure stream-copy. Our tool tries stream-copy first and only re-encodes if necessary.

Will my big camcorder files work?

Browser memory caps WASM at about 2 GB per file. Multi-gigabyte camcorder dumps may need to be split. For files under 2 GB this tool handles them comfortably.

MTS / M2TS / AVCHD to MP4

Sony, Panasonic, Canon and JVC camcorders save footage as MTS or M2TS inside an AVCHD folder. Premiere, Final Cut and most phones won't touch them. Drop a file here to convert it to MP4 in your browser. Big camcorder files OK.

drop an MTS or M2TS file here

or click to choose — AVCHD camcorder footage

What is MTS, exactly?

MTS (or M2TS for the Blu-ray variant) is the file extension AVCHD uses. AVCHD itself is a recording format that Sony and Panasonic created in 2006 for high-def camcorders — H.264 video, Dolby AC-3 audio, MPEG-2 Transport Stream container.

The video inside is normal H.264. The problem is the container. MP4 expects ISO BMFF wrapping; transport streams use 188-byte packets designed for broadcast. Most editors and players were built for MP4 first, MTS second. So you get import errors even though the video itself is fine.

The fix: re-wrap to MP4

The video stream can be copied to an MP4 container without re-encoding — bit-identical, instant. Audio is the question: AC-3 lives fine in MP4 but some software (older Premiere, web players) prefers AAC. Our tool prefers re-encoding audio to AAC 192 kbps for maximum compatibility.

From SD card to MP4 in three steps

Mount your SD card (or copy AVCHD folder to your computer).
Find BDMV/STREAM/*.MTS — that's the actual clips.
Drop one file at a time here.

Multi-cam projects, joined clips

Camcorders split long recordings into 4 GB chunks (FAT32 limit). You'll see 00001.MTS, 00002.MTS, etc. for one continuous shot. Convert each, then use our merge tool to rejoin them seamlessly.

Why browser-based for camcorder footage?

Old camcorder MTS often holds personal family video, weddings, kids growing up — not the sort of thing you upload to a stranger's website. Here, the file stays on your laptop. Drop it, hit convert, you're done.

FAQ

What's the difference between MTS and M2TS?

None functionally. M2TS is what Blu-ray discs use; MTS is what camcorders write. Same format inside.

My MTS file is 8 GB. Will this work?

Probably not in-browser — WebAssembly caps memory around 2–4 GB. For very large files, use a desktop tool or split the file first.

Will I lose quality?

At High preset, no. The video stream is identical to the source.

What about AVCHD folders with multiple .MTS files?

Convert each, then merge with our merge tool — same codecs concat without re-encoding.

Premiere still won't import the result. Why?

Make sure you converted, not just renamed. If you're on Premiere CC with HEVC/AC-3 plugins missing, try opening the MP4 in MediaInfo to verify audio codec is AAC.

Does the file get uploaded anywhere?

No. Disconnect your internet after loading — conversion still works.