Convert M2TS to MTS — Free Online Tool
Convert M2TS Blu-ray disc files to MTS AVCHD format using H.264 video and AAC audio, producing camcorder-compatible transport streams directly in your browser. This conversion strips the Blu-ray-specific container wrapping while preserving the MPEG-2 Transport Stream structure both formats share.
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FFmpeg Command
Copy this command to run the same conversion locally with FFmpeg on your desktop. Download FFmpeg
Drop your M2TS file here
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Settings
Note: Browser-based encoding uses approximate quality targets. For precise CRF compression, copy the FFmpeg command above and run it on your desktop.
Estimated output:
Conversion Complete!
DownloadHow It Works
M2TS and MTS are closely related formats — both use the MPEG-2 Transport Stream container — but M2TS is designed for Blu-ray Disc (BDAV) playback while MTS is the AVCHD standard used by Sony and Panasonic camcorders. During this conversion, the video stream is re-encoded to H.264 (libx264) with a CRF of 23, which is appropriate since the source M2TS may carry H.264, H.265, or VC-1 video that needs to be normalized to the H.264 baseline expected by AVCHD devices. The audio is transcoded to AAC at 128k, replacing higher-bitrate or lossless audio tracks (such as Dolby TrueHD or DTS-HD MA) that are common on Blu-ray sources but unsupported in MTS. Subtitles embedded in the M2TS stream are carried over to the output. The result is a leaner, device-compatible MTS file suitable for playback on AVCHD-capable televisions, editors, and camcorder-based workflows.
What Each Flag Does
| Flag | What it does |
|---|---|
ffmpeg
|
Invokes the FFmpeg binary. In the browser-based tool, this runs via FFmpeg.wasm compiled to WebAssembly, executing the same logic as the desktop version entirely client-side with no server upload. |
-i input.m2ts
|
Specifies the input M2TS file — a BDAV MPEG-2 Transport Stream from a Blu-ray disc or compatible camcorder. FFmpeg reads the 192-byte BDAV packet structure and demuxes the video, audio, and subtitle streams automatically. |
-c:v libx264
|
Re-encodes the video stream to H.264 using the libx264 encoder, which is required for AVCHD MTS compatibility. This step is necessary because M2TS sources may contain VC-1, MPEG-2, or H.265 video that MTS devices and software do not support. |
-c:a aac
|
Transcodes the audio to AAC using FFmpeg's native AAC encoder, replacing any Blu-ray audio format (TrueHD, DTS-HD MA, AC-3, FLAC) with a lossy AAC stream compatible with the MTS/AVCHD specification. |
-crf 23
|
Sets the Constant Rate Factor for the H.264 encode to 23, which is the libx264 default and produces a good balance of quality and file size for HD content. Lower values (e.g., 18) yield higher quality and larger files; higher values (e.g., 28) reduce file size at the cost of visible quality degradation. |
-b:a 128k
|
Sets the AAC audio bitrate to 128 kilobits per second, which is adequate for stereo audio but represents a significant downgrade from lossless Blu-ray audio tracks. Increase to 192k or 256k in the local command if the source has high-quality audio worth preserving more faithfully. |
output.mts
|
Specifies the output filename with the .mts extension, signaling FFmpeg to write a standard MPEG-2 Transport Stream using 188-byte packets in the AVCHD profile, distinct from the 192-byte BDAV structure of the input M2TS file. |
Common Use Cases
- Converting Blu-ray rips stored as M2TS files into MTS so they can be imported into Sony Vegas, Premiere, or other NLEs that have robust AVCHD/MTS project presets
- Preparing M2TS footage captured from a Blu-ray camcorder for ingestion into a Sony or Panasonic AVCHD editing workflow that expects standard MTS file structure
- Downsizing a Blu-ray M2TS file that contains lossless TrueHD or DTS-HD audio into a more portable MTS file with AAC audio for storage on devices with limited codec support
- Archiving BDAV M2TS recordings from a Blu-ray recorder to a format playable on AVCHD-compatible smart TVs and Blu-ray players without full BDAV disc structure
- Re-encoding M2TS files that contain H.265 or VC-1 video into H.264-based MTS so older AVCHD-compatible software or hardware can process them without additional codec packs
- Stripping multi-track audio and subtitle complexity from a Blu-ray M2TS source into a clean, single-track MTS file for sharing or streaming to DLNA devices
Frequently Asked Questions
Yes, some quality loss is expected because the video is re-encoded rather than stream-copied, and the CRF 23 setting produces visually good but not mathematically lossless output. More significantly, if your M2TS source contains lossless audio like Dolby TrueHD or DTS-HD MA, that will be transcoded down to AAC 128k, which is a substantial reduction in audio fidelity. For most HD content at 1080p the visual difference at CRF 23 is minimal, but if you want higher quality, lower the CRF value (e.g., 18) in the FFmpeg command before running locally.
While both formats use the MPEG-2 Transport Stream container, M2TS Blu-ray sources often carry video encoded as H.265 (HEVC), VC-1, or MPEG-2, none of which are part of the AVCHD specification that MTS targets. AVCHD requires H.264 video, so re-encoding to libx264 is necessary to produce a compliant MTS file. If your M2TS already contains H.264 video and you only need a container rename, you could use '-c:v copy' in the FFmpeg command for a lossless passthrough.
Subtitle streams are supported in both M2TS and MTS, and FFmpeg will attempt to carry them through by default with this command. However, multiple audio tracks from the Blu-ray source are not explicitly mapped in this command — only the default audio track will be transcoded to AAC. If you need to preserve a specific audio track or multiple tracks, you would add '-map 0:a:1' (or the appropriate track index) to the FFmpeg command when running it locally.
To improve video quality, lower the CRF value — for example, replace '-crf 23' with '-crf 18' for noticeably sharper output at the cost of a larger file. To increase audio quality, replace '-b:a 128k' with '-b:a 192k' or '-b:a 320k', which is especially worthwhile if your M2TS source has high-quality or lossless audio you want to approximate as closely as AAC allows. Both changes can be made when copying the displayed command and running it locally with FFmpeg.
They share the MPEG-2 Transport Stream foundation but differ in specification and intended use. M2TS uses the BDAV (Blu-ray Disc Audio-Video) wrapper, which includes Blu-ray-specific timing and source packet headers (192-byte packets vs. the standard 188-byte TS packets), and supports codecs like VC-1, MPEG-2, H.265, TrueHD, and DTS-HD MA. MTS is the AVCHD standard targeting camcorder recordings and specifies H.264 video with AC-3 or AAC audio. The file extensions are often used interchangeably in casual conversation, but they are technically distinct profiles.
The single-file command shown on this page can be adapted into a batch script for local processing. On Linux or macOS, you can run: 'for f in *.m2ts; do ffmpeg -i "$f" -c:v libx264 -c:a aac -crf 23 -b:a 128k "${f%.m2ts}.mts"; done'. On Windows Command Prompt, use: 'for %f in (*.m2ts) do ffmpeg -i "%f" -c:v libx264 -c:a aac -crf 23 -b:a 128k "%~nf.mts"'. The in-browser tool processes one file at a time and is best suited for files under 1GB.
Technical Notes
Both M2TS and MTS are rooted in the MPEG-2 Transport Stream specification, but M2TS uses 192-byte source packets (adding a 4-byte Timecode header to the standard 188-byte TS packet) as required by the BDAV specification, while MTS uses standard 188-byte packets as per AVCHD. FFmpeg handles this packet size difference transparently during remux/transcode. A key limitation of this conversion is the loss of Blu-ray-specific audio codecs: TrueHD, DTS-HD MA, and DTS are not supported in MTS, so these will always be transcoded to AAC, introducing lossy compression regardless of CRF setting. Chapters, which are a BDAV/Blu-ray feature, are not preserved in MTS output. If the M2TS source contains HDR metadata (common in UHD Blu-ray H.265 streams), this metadata will be lost during the H.264 re-encode since libx264 does not support HDR10 or Dolby Vision passthrough. For standard 1080p H.264 Blu-ray content, this conversion is essentially a container-level repackaging with audio transcoding, and the quality impact is minimal at the default CRF 23.