AVCHD to M2V Converter

AVCHD to M2V: Read the Two Catches First

An .m2v file is a raw MPEG-2 video elementary stream. Not a container — a bare stream of MPEG-2 pictures with a sequence header at the front and nothing wrapped around it. Two consequences follow, and both surprise people who expected a normal video file: the sound is gone, and MPEG-2 has a bitrate floor that decides your file size for you. This page is about both, because everything else on the page is straightforward.

The Output Has No Audio and No Duration

Your AVCHD clip carries Dolby AC-3 or linear PCM alongside the H.264 picture. An M2V stream cannot carry audio at all, so the muxer silently drops it. In our testing the encoder log for a 5-second AVCHD source ended with video:8367KiB audio:0KiB — the audio track was read, decoded and then thrown away without an error.

The same bareness costs you metadata. Probe an .m2v and the duration and bitrate come back as unknown, because there is no container header to record them; a player has to scan the whole stream to work out how long it is. That is normal for an elementary stream and not a sign of a bad file.

Because there is no audio path, the Audio Codec group on this page renders with no selectable codecs at all — every entry in it is suppressed. If you need the soundtrack, export it separately with AVCHD to AC3 and let your authoring tool multiplex the two streams, which is exactly the workflow DVD authoring expects.

How to Convert AVCHD to M2V

1. Upload Your AVCHD File: Drop your .avchd file on the page or click "+ Add Files"; several can be queued and each produces its own .m2v. The upload validator matches the extension exactly, so a camcorder file still named .MTS belongs on MTS to M2V instead. Files are uploaded over an encrypted connection, processed on our servers, and deleted automatically after a few hours — no sign-up, no watermark, never shared or made public.
2. Leave the Video Codec on MPEG-2: MPEG-2 is what this page opens on and the only codec that makes an .m2v mean anything. H.264, H.265, MPEG-1, MPEG-4, DivX, Xvid, MJPEG, H.261 and H.263 are all offered in the dropdown, but writing any of them into a file called .m2v produces something no MPEG-2 decoder will parse.
3. Set the Video Resolution — This Is Your Real Size Control: "Keep original" is preselected, and the height presets, percentage and explicit Width / Height / Width × Height inputs are all available. Because of the bitrate floor described below, resolution is the lever that actually moves the output size. For DVD authoring use 720 × 480 (NTSC) or 720 × 576 (PAL).
4. Pick a Rate-Control Mode and Convert: Quality Preset opens the File Compression group with seven rungs; Constant Bitrate, Variable Bitrate and Specific file size are also there. Trim → Time Range takes a start time and duration if you only want part of the take. Click Convert to download.

The MPEG-2 Bitrate Floor, by Output Resolution

MPEG-2 fails outright if you ask it for a bitrate that is too low for the frame size, so the pipeline calculates a minimum from the output resolution and raises anything below it. The bpp figure below is the bits-per-pixel assumption at an assumed 30 fps, and everything is clamped to at least 2 Mbit/s:

This is why asking a 1080p AVCHD clip for a 2 Mbit/s M2V appears to do nothing: the request is below the floor, so 7.46 Mbit/s is used instead. Drop the resolution and the floor drops with it — that is the mechanism, and it is the reason step 3 matters more than step 4.

Which Rate-Control Modes Actually Reach the Encoder

The Constant Quality slider on this page runs 1–31 and opens at 5, which looks like a working qscale control because on most other codecs it is one. On MPEG-2 it is not. If you want fine control over size, use Specific file size or Variable Bitrate and keep an eye on the floor.

Frequently Asked Questions

Why does my M2V file have no sound?

Because M2V is a video-only elementary stream — there is no place in the format to put an audio track. The conversion decodes your AVCHD clip, encodes the picture as MPEG-2 and discards the sound. This is expected behaviour for the format rather than a fault, and it is the normal handoff for DVD and broadcast authoring tools, which want video and audio as separate files.

How do I get the audio back for DVD authoring?

Export it separately and let the authoring application multiplex. AVCHD to AC3 produces the Dolby Digital track that DVD-Video and AVCHD both specify, and tools like DVDStyler or AVStoDVD will take an M2V plus an AC-3 and build the program stream themselves. Keep the two exports the same length — trim both, or neither — or they will drift out of sync.

Why doesn't lowering the bitrate make the file smaller?

Because MPEG-2 refuses to encode below a resolution-dependent minimum, and the pipeline raises any request that falls under it rather than letting the encode fail. At 1920 × 1080 that minimum is about 7.5 Mbit/s, so a 2 Mbit/s request is quietly replaced. Lower the output resolution instead — the floor is calculated from the frame size you are writing, not the one you uploaded.

Is the CRF slider on this page doing anything?

Not on MPEG-2. Constant Quality and Constraint Quality are both converted into a plain bitrate target set to the resolution minimum, so moving the slider changes nothing about the output. The control renders because the same File Compression group is shared with codecs where it does work. Use Quality Preset, a bitrate mode, or Specific file size instead.

Will my 1080i AVCHD footage be deinterlaced?

No. There is no deinterlacing step anywhere in this pipeline, so interlaced fields survive into the MPEG-2 stream with the combing intact. For DVD authoring that is usually what you want, since DVD-Video is an interlaced format. If the M2V is headed somewhere progressive, deinterlace in an editor first and upload the result.

Can VLC or my media player open a .m2v directly?

Most desktop players will, because they probe the stream rather than trusting the extension — VLC and MPV both handle raw MPEG-2 elementary streams. What they cannot do is show a reliable timeline until they have scanned the file, since there is no container header carrying the duration. Web browsers and phone galleries generally will not open one at all.

Is this the same thing as an MPG or VOB file?

No, and the difference matters if you are handing the file to authoring software. An .m2v is video only. An .mpg is an MPEG program stream, which multiplexes video and audio together, and a .vob is that program stream with DVD-specific structures added. If you want one playable file rather than a pair of elementary streams, AVCHD to MPG is the target you actually want.

Does re-encoding H.264 to MPEG-2 lose quality?

Yes, unavoidably. MPEG-2 is roughly a generation behind H.264 in efficiency, so matching the look of an AVCHD source needs noticeably more bits — that is exactly why the minimum-bitrate table exists. Expect the M2V to be larger than the source at comparable quality, and treat this conversion as a compatibility step for MPEG-2-only tooling rather than an archival one.

What frame rate does the output use?

Whatever the source has — the conversion does not resample timing, so a 1080/50i or 1080/60p AVCHD clip keeps its rate. That is worth checking against your target: DVD-Video expects 29.97 fps for NTSC and 25 fps for PAL, so a 50p or 60p AVCHD recording will need a frame-rate conversion in your authoring tool even though the M2V itself is valid.