MP4 to M2TS Converter

MP4 to M2TS Converter

M2TS is the BDAV flavour of the MPEG-2 transport stream — the container Blu-ray discs and AVCHD camcorders store video in. Converting an MP4 to M2TS is normally a step in a disc-authoring or camcorder-style workflow, where the tool downstream expects transport-stream packets rather than the box structure an MP4 uses. This page re-encodes your MP4 into that container with the codec, quality and resolution you choose. Files upload over an encrypted connection, are processed on our servers, and are deleted automatically after a few hours — no sign-up, no watermark.

M2TS at a Glance

MP4 at a Glance

The structural difference is the whole point. An MP4 keeps one big index at the front or back of the file, which is efficient for seeking but useless if the stream is being read as it arrives. A transport stream interleaves everything into small fixed-size packets that can be decoded from any point — which is what a disc player's hardware and a camcorder's write path both expect.

How to Convert MP4 to M2TS

1. Upload Your MP4 File: Drag and drop your .mp4 or .m4v, or click "Add Files" to browse. Several videos can be queued and converted with identical settings.
2. Pick a Video Codec and Audio Codec: Open Advanced Options. Video Codec starts on H.264, which every Blu-ray player is required to decode. Audio Codec starts on AAC — change it to AC3 if the file is headed for disc-authoring software, since AAC is not one of the codecs the AVCHD specification allows.
3. Set the Quality and Resolution (Optional): File Compression starts on Quality Preset at Very High (Recommended). Alternatives are Specific file size, Constant Bitrate, Variable Bitrate, Constant Quality (a CRF value from 16 to 51) and Constraint Quality. Video resolution starts on "Keep original"; the Preset Resolutions dropdown sets the height — pick 1080p for the AVCHD ceiling and the width follows the source aspect ratio.
4. Trim and Convert: Switch Trim from Unchanged to enter a Start time and Duration if you only need part of the clip, then click Convert and download the .m2ts.

What You Get, and What You Don't

The output really is BDAV-framed: packets are 192 bytes, each one a 4-byte arrival-timestamp header followed by the 188-byte transport packet with its 0x47 sync byte. That is what distinguishes an .m2ts from a plain .ts, and it is the framing disc tools look for.

What a single converted file is not is a disc. Blu-ray and AVCHD structure lives in a folder tree — BDMV, STREAM, playlist and clip-information files — and one stream on its own carries none of that. Authoring software builds it. Similarly, dropping an .m2ts onto a data disc does not make a disc a player will treat as video.

Three limitations worth knowing before you convert, because none of them can be worked around inside this page:

• Interlaced sources stay interlaced. There is no deinterlacing step, so combing baked into old camcorder or broadcast footage survives into the output. Deinterlace first in a video editor if the target is progressive.
• HDR is not tone-mapped. HDR footage from a recent phone gets a plain colour conversion and generally comes out looking flat or washed out. Convert to SDR first if colour matters.
• Non-square pixels are not corrected. Anamorphic and legacy standard-definition sources can come out geometrically wrong; set an explicit Width × Height under Video resolution to force the display shape you want.

Frequently Asked Questions

Is the output a real BDAV stream, or just an MP4 with a different extension?

It is a real transport stream. The video and audio are fully re-encoded and remultiplexed, and the result uses BDAV's 192-byte packet framing — a 4-byte arrival-timestamp header in front of each 188-byte MPEG-2 TS packet. Nothing is copied through untouched, so what you download is a genuine .m2ts, not a renamed MP4. That is also why a conversion takes real time rather than finishing instantly.

Can I burn this file straight to a Blu-ray?

Not on its own. A playable Blu-ray needs the full BDMV folder structure — the stream files live under BDMV/STREAM, alongside playlists, clip information and index files that a player reads first. This converter produces the stream; authoring software produces the structure around it. Feed the .m2ts into your authoring tool as the source clip and let it build the disc image.

Which audio codec should I choose for a disc project?

AC3. The Audio Codec dropdown starts on AAC because that is the general-purpose default for this container, but AAC is not among the codecs the AVCHD specification permits — that list is Dolby Digital (AC-3) and uncompressed linear PCM. Spec-strict authoring tools and some set-top players will reject or silently drop an AAC track. If the file is only ever going to be played by VLC or a computer, AAC is fine; if a disc or a camcorder is involved, switch to AC3 before converting.

Should the video be H.264 or MPEG-2?

H.264 for almost everyone. Blu-ray players are required to decode MPEG-2, H.264/AVC and SMPTE VC-1, so all three are legal, but H.264 delivers far better quality per megabyte, which matters when you are fitting a long programme onto a disc. MPEG-2 is worth choosing only when a legacy tool or an older DVD-derived workflow specifically demands it. One practical note: if you do switch to MPEG-2, MPEG-4, Xvid or DivX, use Constraint Quality rather than Constant Quality — those codecs use a different quality scale, and Constraint Quality behaves predictably on them.

Is M2TS the same thing as the MTS files from my camcorder?

Same container, two extensions. AVCHD camcorders write .MTS on their own media because the card's filesystem follows the legacy 8.3 naming convention; the same stream takes the longer .m2ts name once imported to a computer or placed on a disc. If you specifically need the camcorder spelling, use the MP4 to MTS converter instead — note that .ts and .mts outputs use plain 188-byte packets, while .m2ts gets the 192-byte BDAV framing.

What resolution and bitrate should I target?

For AVCHD, the ceiling is 1920×1080 at up to 24 Mbit/s, or 28 Mbit/s in AVCHD Progressive mode. Staying at or below that keeps the file inside what camcorder-oriented tools expect. Pick 1080p from Preset Resolutions — the dropdown sets height and derives width from the source aspect — and either leave Quality Preset on Very High or switch to Constant Bitrate and type an explicit rate if a tool downstream demands a specific one.

Why is my M2TS a different size from the MP4 I started with?

Because it is a fresh encode, not a repackage. Transport-stream framing adds a few percent of overhead on its own — those 4-byte headers on every 192-byte packet are about 2% before anything else — but the dominant factor is the quality setting you chose. Quality Preset targets a quality level rather than a size, so a heavily compressed source can grow and a lightly compressed one can shrink. Use "Specific file size" if you need to land on a number.

Will subtitles, chapters or multiple audio tracks come across?

Treat this as a single video plus single audio conversion. Chapter markers and soft subtitle tracks belong to the MP4's box structure and have no direct equivalent in the output here, and disc-level subtitle formats are built by authoring software rather than carried in the stream. If your source has several audio tracks, plan on the conversion producing one. Keep the original MP4 as the master if any of that metadata matters.

What happens to my video after conversion?

It is uploaded over an encrypted connection, converted on our servers, and deleted automatically after a few hours. There is no account requirement and no watermark, and files are never shared or made public. To go the other direction and get a widely playable file back, use the M2TS to MP4 converter.