How to Convert MTS and M2TS Camcorder Files
You plugged the camcorder in, copied the card, and every clip is a .MTS file that Windows previews as a black rectangle and your editor refuses to import. Nothing is wrong with the footage — it is simply wrapped in a broadcast container built for recording, not for computers. Here is what AVCHD is, which format to convert to, and how to do it without sending hours of family video to a stranger's server.
Morphix MTS → MKV converter
Camcorder streams into a flexible container that keeps every audio track. MP4 output is one click away too.
What AVCHD actually is
AVCHD is a recording specification, not a single file format. The camera encodes H.264 video and AC3 or PCM audio, then wraps them into an MPEG transport stream — the same packet-based structure used for satellite and terrestrial broadcast. That structure is chosen because it survives dropouts and power loss on a memory card, which is exactly the opposite of what an editing timeline wants.
The consequence is that the video inside your MTS file is perfectly ordinary and widely supported, while the wrapper around it is not. Most conversion problems disappear once you understand that you are changing the packaging, not the picture.
MKV or MP4 — choosing the target
MP4 is the right answer whenever the clip has somewhere to go: a phone, a smart TV, a messaging app, a social upload or a colleague on an unknown machine. It is the most broadly supported video container in existence and every editor imports it without complaint.
MKV is the right answer when the clip is going into an archive. It carries multiple audio tracks, chapter markers, subtitles and unusual codecs without conversion losses, which matters for multi-microphone shoots or footage you may want to remaster later. Many people keep an MKV master and export MP4 copies for sharing.
Step by step
- Copy the entire AVCHD or PRIVATE folder off the SD card before touching anything — never convert directly from the card.
- Open the Morphix MTS or M2TS converter in your browser.
- Drag in all the clips from one recording session at once; batch conversion runs file by file locally.
- Pick MKV for an archive master, or MP4 if the clip is going straight to a viewer.
- Download the results and import them into your editor in numeric order.
Why the files come in 2 GB chunks
Camcorder cards are usually formatted with a filesystem that cannot hold a single file above roughly 2 GB, so the camera silently starts a new file when it reaches the ceiling. A twenty-minute recording can therefore arrive as four or five clips with sequential numbers.
The split is frame-accurate: laid end to end in the same order, the clips reproduce the original recording exactly. Convert each one, drop them onto the timeline in numeric order, and the join is invisible. Sorting by filename rather than by modification date matters here, because copying can scramble timestamps.
The privacy angle nobody mentions
Think about what is actually on a camcorder card: weddings, birthdays, children, the inside of your home, conversations recorded without anyone considering an audience. Standard online converters ask you to upload every gigabyte of that to a server you know nothing about, where it sits until some retention policy deletes it.
Converting in the browser removes the question. The decoder runs as WebAssembly inside your tab, reads the file from disk, writes the result back to your downloads folder, and never opens a network connection. You can confirm it yourself by watching the Network panel stay silent while a 4 GB clip converts.
FAQ
What is an MTS file?
MTS is the file extension AVCHD camcorders write onto SD cards. Inside is an MPEG transport stream carrying H.264 video and AC3 or PCM audio, packaged in fixed-size packets designed for reliable recording rather than for editing or playback on a computer.
What is the difference between MTS and M2TS?
They are the same transport stream with different packaging conventions. M2TS is the Blu-ray flavour with a timestamp prefix on each packet and is what you find once footage is copied into an AVCHD folder structure or onto a disc; MTS is what appears directly on the camera card.
Should I convert AVCHD to MP4 or MKV?
Convert to MP4 when the clip is going to a phone, a TV, a social platform or a colleague. Convert to MKV when you want to keep multiple audio tracks, chapters or unusual audio codecs intact for archiving, because MKV imposes almost no restrictions on what it can carry.
Does converting AVCHD lose quality?
Remuxing the same H.264 stream into a new container is lossless. Re-encoding — which happens whenever the target needs a different codec or a smaller size — is lossy, though at sensible bitrates the difference on camcorder footage is not visible in normal viewing.
Why is my footage split into several files?
AVCHD splits a long recording into roughly 2 GB chunks because of filesystem limits on the card. The chunks are meant to be played back-to-back, so convert each one and join them on the timeline in your editor, in the order the camera numbered them.
Is it safe to convert family footage online?
Only if the conversion happens locally. Uploading home video puts hours of your family, your home interior and your children onto a third-party server with retention policies you never read. Browser-based conversion keeps every frame on your own machine.