MTS to AVCHD Converter

MTS vs AVCHD — Aren't They the Same Thing?

Yes — and this is the most useful thing to know before converting. An .mts file is AVCHD: "AVCHD" is the recording format Sony and Panasonic introduced in 2006, and .MTS is simply the filename a camcorder writes when it records in that format. There is no separate "AVCHD format" to convert into. What people usually mean by "AVCHD" the destination is the full disc/card folder structure — the BDMV directory tree, not a single file — and that is the one real distinction this page exists to explain. If you just need footage that plays everywhere, you almost certainly want MTS to MP4 instead.

A Bare .mts Stream vs a Full AVCHD Structure

This tool re-encodes your .mts clip and outputs a stream with an .avchd extension. What it cannot do is author the multi-folder AVCHD disc structure that authoring software and Blu-ray players expect — that requires a disc-authoring tool, not a file converter (the same way a single .vob file is not a finished DVD).

Spec note: AVCHD 1.0 (2006) caps video at 24 Mbit/s (18 Mbit/s on DVD media); the 2011 AVCHD 2.0 amendment raised that to 28 Mbit/s and added 1080/50p–60p (AVCHD Progressive) and 3D. The codecs never changed — H.264 video, AC-3 or LPCM audio throughout.

When This Conversion Makes Sense

• You need a normalized H.264 stream — re-encoding to a single consistent profile/bitrate from mixed-camera footage, accepting a small generation loss for uniform output.
• A specific tool demands an .avchd-named stream — some pipelines key on the extension; this tool gives you one.
• You want to resize, trim, or change bitrate while keeping the AVCHD codec family (H.264 + AC-3).

When You Want Something Else

• You just want footage to play everywhere — phones, browsers, TVs, social uploads → MTS to MP4. MP4 carries the same H.264 into a container the whole world plays.
• You want the least quality loss — set Constant Quality to a low CRF (around 18 is visually lossless); every conversion here re-encodes rather than stream-copying, so nothing is truly bit-for-bit, but a low CRF keeps the difference imperceptible.
• You have the reverse problem — a file already named .avchd and want a plain .mts → AVCHD to MTS.
• You need to author a playable AVCHD disc — that is a disc-authoring job (the full BDMV tree), not a file conversion.

AVCHD 1.0 vs AVCHD 2.0 at a Glance

The 2011 revision raised bitrate and added progressive-scan modes, but the codecs never changed — so a re-encode stays inside the same H.264 + AC-3 family either way.

How to Convert MTS to AVCHD

1. Upload Your MTS File: Drag and drop or click "+ Add Files" to select clips from your computer or a mounted SD card. AVCHD camcorders store recordings under PRIVATE/AVCHD/BDMV/STREAM/ with 8.3-style names like 00001.MTS. Batch upload is supported.
2. Pick a Quality Preset: Under File Compression, the default "Very High (Recommended)" preset keeps near-source H.264 quality. Switch to Specific file size for a megabyte budget, Constant Bitrate for a fixed rate, Variable Bitrate for download, or Constant Quality to set a CRF directly.
3. Resize or Trim (Optional): Under Video resolution, keep original, scale by Resolution Percentage, choose a Preset Resolution, or enter custom Width x Height. Use Trim → Time Range to keep only part of a clip.
4. Convert and Download: Click Convert. Files are uploaded over an encrypted connection, processed on our servers, and deleted automatically a few hours after conversion — no sign-up, no watermark, never shared.

Frequently Asked Questions

Is MTS already AVCHD, so why would I convert it?

Yes — a .mts file is already AVCHD; the extension is just the camcorder's filename for an AVCHD recording. There is no separate format to gain. The honest reasons to run this conversion are practical: re-encoding mixed footage to one consistent H.264 profile, hitting a target bitrate or size, trimming, or feeding a tool that specifically expects an .avchd-named stream. If your goal is broad playback, convert to MP4 instead — you get more compatibility, not less.

Will this build a playable AVCHD disc structure I can burn?

No. This is a file converter — it outputs a single re-encoded stream, not the full PRIVATE/AVCHD/BDMV/ directory tree with the playlist and clip-information files that AVCHD players and Blu-ray authoring tools read. Building that structure is a disc-authoring task, much like a lone .vob file is not a finished DVD. Use dedicated authoring software if you need a disc; use this tool if you just need a stream.

Will converting lose quality?

A small amount, because the output is re-encoded rather than copied. At the default Very High preset the difference from the source is visually hard to spot, but it is not bit-for-bit. Since the input is already H.264, re-encoding to H.264 gains no format advantage — so if preservation matters, set Constant Quality to a low CRF (around 18 is near-lossless). No conversion here is a true stream copy; even MTS to MKV, which keeps the same H.264 codec family, re-encodes the video rather than copying it.

What is the difference between .MTS and .M2TS?

Both are MPEG-2 transport streams carrying H.264 video and AC-3 (or LPCM) audio, and there is no functional difference between them — one can be renamed to the other. .MTS is what AVCHD camcorders write to SD cards using 8.3 filenames; .M2TS is the same stream after import to a computer or as authored on a Blu-ray Disc's BDMV/STREAM/ directory.

Does the output keep the original resolution and audio?

Resolution: yes — leave "Keep original" under Video resolution and the output matches the source dimensions (AVCHD typically records 1920x1080; AVCHD 2.0 also covers 1080p60). Audio: the AVCHD family uses Dolby AC-3 or linear PCM, and the converter keeps an AVCHD-compatible audio track. If a downstream player drops AC-3 (a common licensing quirk in consumer software), an MP4 output re-encoded to AAC avoids the silent-audio trap.

What CRF should I set to keep near-lossless quality?

Switch File Compression to Constant Quality and choose a low CRF — around 18 is visually lossless for H.264, while the default Very High preset already stays close to the source. Lower numbers mean higher quality and a larger file. There is no true stream copy here, so a low CRF is the way to keep the re-encode imperceptible rather than expecting a bit-for-bit copy.

Can I convert an .avchd file back to a plain .mts?

Yes. Because both are the same MPEG-2 transport stream carrying H.264 and AC-3, the difference is effectively the filename, not the codec. Use AVCHD to MTS if a tool specifically wants the .mts extension; the stream inside is treated the same in either direction (still re-encoded, not stream-copied).

How are my files handled, and is there a size limit?

Files are uploaded over an encrypted connection, processed on our servers, and deleted automatically a few hours after conversion — no sign-up, no watermark, and nothing is shared or made public. There is no fixed per-file cap; the practical limit is upload size and connection speed. In our testing, a 2-minute 1080p MTS clip at the default preset uploads and converts comfortably; a full camcorder reel of several gigabytes works too, it just takes longer to upload.