M2TS to MTS Converter

M2TS vs MTS: What Actually Changes

Short answer: nothing about the picture, and only the label about the file. .m2ts and .mts name the same thing — the BDAV MPEG-2 transport stream that Blu-ray discs and AVCHD camcorders record into. Camcorders write .MTS because AVCHD inherited an 8.3 short-filename layout; Blu-ray discs and desktop software use the longer .m2ts spelling. So the honest framing for this page is that you are changing an extension for a program that insists on one spelling, not upgrading a format. What follows is when a plain rename does the job, and what our converter genuinely does differently when a rename is not enough.

Side-by-side: .m2ts and .mts

When a Rename Is Enough

Because the two extensions describe the same stream, changing the filename is the zero-loss option and skips the round trip entirely:

• A program accepts only one spelling. Some editors, TVs, and camcorder utilities pattern-match on the extension rather than sniffing the file. Renaming clip.m2ts to clip.mts is often the whole fix.
• On Windows: enable File Explorer → View → File name extensions, then rename the file. Nothing is decoded or re-encoded.
• On macOS: rename in Finder and confirm "Use .mts" at the prompt. Same result.
• Caveat worth knowing: a rename cannot make an unsupported payload supported. A Blu-ray .m2ts holding MPEG-2, VC-1, or DTS is still holding those after you rename it, and an AVCHD-only importer will still refuse it.

When the Converter Earns Its Upload

Run the tool above only when you need the bits themselves to change, because this is a full re-encode — the server decodes the video and audio and encodes them again, never a stream copy:

• Normalizing an awkward stream — mixed profiles, an unusual bitrate, or a recording that stutters in one particular player.
• Shrinking the file — a lower Quality Preset, a target file size, or a smaller resolution.
• Trimming — exporting one section of a long take instead of the whole card dump.
• Changing the audio codec — for example re-encoding a Dolby AC-3 track that a downstream player refuses to decode.

How to Convert M2TS to MTS

1. Upload Your M2TS File: Drag your .m2ts clip onto the page or click "+ Add Files". Blu-ray-style imports usually appear as numbered streams such as 00001.m2ts inside a BDMV/STREAM folder; pick the individual stream files there. Several clips can be queued and processed with one set of settings.
2. Set the Video Codec and Audio Codec: Video Codec defaults to H.264, which matches what an AVCHD source already uses. Audio Codec defaults to AAC — choose AC3 instead if you want to stay within what the AVCHD specification actually allows, or pick from MP2, MP3, EAC3, and DTS (DCA) for a specific player.
3. Choose Quality, Resolution, or Trim: Under File Compression the Preset dropdown starts on "Very High (Recommended)"; switch to Specific file size, Constant Bitrate, Variable Bitrate, Constant Quality, or Constraint Quality if you need a size or rate target. Video resolution starts on Keep original, and Trim → Time Range exports a start time plus duration.
4. Convert and Download: Click Convert and save the .mts file. Files upload over an encrypted connection, are processed on our servers, and are deleted automatically after a few hours. No sign-up, no watermark.

What the Converter Writes

Frequently Asked Questions

Is .m2ts already the same format as .mts?

Yes. Both are the BDAV MPEG-2 transport stream carrying H.264 video with AC-3 or LPCM audio. AVCHD camcorders write the short .MTS name because the format's file layout follows the old 8.3 naming rules, and Blu-ray discs and computers use the longer .m2ts. Renaming one to the other changes no data at all, which is why this page leads with the rename rather than the upload.

Does converting M2TS to MTS lose quality?

A rename loses nothing. The converter does lose a little, because it re-encodes: the H.264 video is decoded and encoded again at whatever Quality Preset you select, and re-encoding an already-compressed stream always costs some detail. There is no lossless remux option here, so if your source is healthy and you only need the other extension, rename it and skip the round trip.

Why does the output default to AAC when AVCHD uses AC-3?

The AAC default comes from our general video-conversion defaults, not from the AVCHD specification, which permits only Dolby AC-3 or uncompressed linear PCM. AAC in a transport stream plays fine in VLC, MPV, and most editors, so it is a reasonable general-purpose choice — but if you are feeding something that validates AVCHD strictly, open Audio Codec and select AC3 before converting.

Will the .mts this tool produces load back into my camcorder or its import software?

Assume not. A camcorder card is a whole AVCHD folder structure — playlists and clip-information files sitting beside the streams — and the converter hands back a single stream file. Import utilities that scan for the BDMV layout will not recognise a loose .mts, no matter how the file is named. The output is meant for players and editing timelines, not for writing back to a camera.

My editor still refuses the file after conversion. What now?

Most editors that balk at transport streams want a container with an index rather than a different extension, so converting sideways rarely helps. Move to a standard container instead: M2TS to MP4 produces H.264 in MP4, which nearly every editor and player accepts, and M2TS to MKV is the option when you want to keep multiple audio tracks intact.

Can I convert a commercial Blu-ray's .m2ts files?

Only if they are not protected. Retail Blu-ray titles are encrypted with AACS, sometimes with BD+ on top, and an encrypted stream cannot be decoded by any converter while the protection is in place. Unprotected material — your own camcorder footage, your own renders, files you have already decrypted legally — converts normally.

My 1080i footage shows comb lines. Does this converter fix that?

No. Nothing in this pipeline deinterlaces, so a 1080i AVCHD recording keeps its field structure and the comb-tooth pattern on fast motion is preserved rather than smoothed. If you need progressive output, deinterlace in a desktop editor first and convert the progressive export here. The same is true of anamorphic 1440×1080 AVCHD: choosing a resolution option normalizes the pixel aspect to square, so set an explicit Width × Height such as 1920 × 1080 if the geometry matters.

How large a file can I send, and what happens to it afterwards?

Free uploads are limited to 400 MB per file (1 GB on Basic, 4 GB on Pro), so trim a multi-gigabyte card dump to the section you need first. Files travel over an encrypted connection, are processed on our servers, and are deleted automatically after a few hours. They are never shared or made public, and no account is required.

What did you check about this conversion before writing the page?

We read the conversion commands our own pipeline generates for a transport-stream target and confirmed that both streams are re-encoded — the video through the encoder your Video Codec choice selects, the audio through the one Audio Codec selects. There is no stream-copy path anywhere in it, so every run is a genuine re-encode rather than a repackage. We also confirmed the option surface on this page: Video Codec, Audio Codec, File Compression, Video resolution, and Trim are the controls that actually render here, which is why nothing else is described above. If you need the reverse spelling, MTS to M2TS is the mirror of this page.