MTS to MPEG Converter

Turning AVCHD Camcorder Footage into an MPEG Program Stream: What This Covers

MTS is the file an AVCHD camcorder writes to its card — H.264 video with Dolby Digital or Linear PCM audio inside an MPEG-2 transport stream, per the AVCHD specification. An .mpeg file is the older MPEG program stream: MPEG-1 or MPEG-2 video with an MPEG audio track, the thing DVD-authoring software, set-top recorders, kiosk players, and a lot of institutional video systems still expect. (.mpg is the same format under a shorter name — MTS to MPG is the identical tool with that extension.)

This walk-through covers the part that trips people up. MPEG-2 does not have a quality dial in the sense that H.264 does, and this page shows controls that look like one. What actually determines how your MPEG turns out is the output frame size and the bitrate, and the sections below explain exactly which controls reach the encoder and which are quietly discarded.

How to Convert MTS to MPEG

1. Upload Your MTS File: Drag the .mts clip onto the page or pick it with the file browser. Several clips can be queued and they convert with the same settings.
2. Confirm Video Codec and Audio Codec: Video Codec opens on MPEG-2, which is what DVD authoring and almost every legacy MPEG workflow needs; MPEG-1 is there for much older targets. Audio Codec opens on MP2, with AC3, MP3, and DTS (DCA) also offered.
3. Set Video resolution, then a Bitrate Mode: Under Video resolution, choose Width x Height and type exact pixel dimensions if you are targeting a disc; otherwise Keep original holds the camera's frame size. Then set File Compression to Constant Bitrate, Variable Bitrate, or Specific file size and give it a real number.
4. Convert and Download: Start the job and save the .mpeg. Files upload over an encrypted connection, are processed on our servers, and are deleted automatically a few hours later — no sign-up, no watermark, never shared or made public.

Walk-through: Why Only Resolution and Bitrate Move the Output

MPEG-2 predates constant-quality encoding. It has no CRF, so our encoder handles the quality-style modes by translating them into a bitrate — and for the two CRF-shaped controls that translation throws your number away entirely:

• Constant Quality and Constraint Quality show a numeric box on this page, but with MPEG-2 selected the value never reaches the encoder. The job is rewritten to use a minimum bitrate computed from the output frame size, and a note is logged saying the codec has no quality mode. Setting that box to 2 or to 31 produces the same encode. Do not use these two modes here.
• Quality Preset does something, but indirectly: with no CRF available it scales the source clip's bitrate, from roughly 0.3x at Lowest to 1.5x at Highest. On high-bitrate AVCHD that gives you real control at the top of the range, but the lower rungs fall through the floor described below and converge on the same result.
• Constant Bitrate, Variable Bitrate, Custom Bitrate, and Specific file size are the modes that behave the way their names suggest. Give one of them a number and that is what the encoder aims at.

The floor is the second half of the story. MPEG-2 fails outright if it is asked to encode a large frame at too few bits, so the pipeline computes a minimum from the output pixel count and raises anything below it. That minimum is why "make this small" requests on full-HD MPEG-2 stop working at a certain point — and why dropping the resolution is the lever that actually shrinks the file:

Getting the Frame Size Exactly Right

If you are feeding DVD-authoring software, the frame size is not negotiable: DVD-Video is standard definition, 720x480 at 29.97 fps for NTSC or 720x576 at 25 fps for PAL. There is a catch in how our resolution presets work, and it matters here.

The Preset Resolutions list sets height only — width follows the source aspect ratio. Choosing 480p on a 16:9 1080p clip therefore yields 854x480, not 720x480, and a DVD authoring tool will reject it. To get a disc-legal frame you must choose Width x Height under Video resolution and type the numbers yourself. Check the unit dropdowns while you are there: they open on Percent (%), so switch both to Pixels before entering 720 and 480.

Which Audio Track to Put in the MPEG

Common Errors and How to Fix Them

• "Nothing I do to the quality slider changes the file." You are on Constant Quality or Constraint Quality with MPEG-2 selected. Those two are inert here. Switch to Constant Bitrate or Specific file size.
• "The authoring software rejects my MPEG." Almost always the frame size. Use Width x Height in pixels — 720 x 480 or 720 x 576 — rather than a Preset Resolution, which only sets height.
• "The file will not get any smaller." You have hit the resolution-derived minimum bitrate in the table above. Reduce the output frame size and the floor drops with it.
• "There is no sound after import." Some legacy players only read MP2 or AC3 from a program stream. If you selected MP3 or DTS, re-run with MP2.
• "The MPEG is much bigger than the MTS." Expected. MPEG-2 is roughly a codec generation behind H.264, so matching the same picture takes noticeably more bits.

When This Doesn't Work

If all you want is footage that plays on a phone, laptop, or smart TV, MPEG is the wrong destination — you are re-encoding modern HD into a 1990s codec and getting a bigger, softer file for it. MTS to MP4 is the right call there. This page also produces a single program-stream file, not a disc: if you need the VIDEO_TS folder structure and .VOB files that a DVD player actually reads, convert with MTS to VOB and author the disc in software that builds that layout. And a clip that was copied off the card mid-write is truncated at the source — re-copy it from the camcorder rather than expecting a converter to repair it.

Frequently Asked Questions

Why does changing the Constant Quality number make no difference?

Because MPEG-2 has no constant-quality mode, and our encoder is explicit about it: when it receives a Constant Quality or Constraint Quality request for MPEG-2 it discards the value, substitutes a minimum bitrate derived from the output frame size, and records that the codec has no quality mode. The input box still renders — that is the honest answer to why it looks functional — but nothing you type there reaches the encoder. Use Constant Bitrate, Variable Bitrate, or Specific file size, all of which are respected.

What resolution do I need for DVD authoring, and why isn't there a 720x480 preset?

DVD-Video is standard definition only: 720x480 at 29.97 fps for NTSC regions, 720x576 at 25 fps for PAL regions. Our Preset Resolutions list is height-based — the width is derived from the source's aspect ratio — so picking 480p on 16:9 footage gives you 854x480 and the authoring tool refuses it. Choose Width x Height instead, switch the unit dropdowns from Percent to Pixels, and type the exact numbers.

Which audio codec should the MPEG carry?

Leave it on MP2 unless you have a reason not to; it is the audio format legacy MPEG players are most likely to read. Choose AC3 if you are heading for DVD authoring or a home-cinema receiver — that is Dolby Digital, the same family your camcorder recorded, though it is still re-encoded rather than passed through. MP3 and DTS (DCA) are available but neither is part of the DVD-Video audio set, so verify your target accepts them first.

Why is the MPEG bigger than the MTS it came from?

Because MPEG-2 is substantially less efficient than H.264. Your camcorder used a codec designed in the 2000s; MPEG-2 was standardised as ITU-T H.262 in 1995, jointly with ISO/IEC. To hold the same visual quality at the same frame size, the older codec needs considerably more bits. The way to a smaller file here is a smaller frame — drop the output resolution and the minimum bitrate drops with it — not a lower quality setting.

Does converting to MPEG fix the interlacing in my 1080i clips?

No. Nothing in this pipeline deinterlaces, at any stage or under any setting. If your AVCHD footage was recorded 1080i, each frame holds two fields captured moments apart, and the comb pattern on moving subjects is encoded straight through into the MPEG. This is worth knowing precisely because interlaced sources are common on camcorders and MPEG-2 is happy to carry interlaced video. If you need progressive output, deinterlace with a desktop tool before or after converting.

Can I burn the file this produces straight to a DVD?

Not directly. A DVD-Video disc is a folder structure — VIDEO_TS holding .VOB, .IFO, and .BUP files — not a single .mpeg. What you get here is a compliant-ish program stream to feed into authoring software, which builds that structure, adds the menus and chapter marks, and multiplexes the audio. If you want the disc-native object rather than the intermediate, MTS to VOB produces .VOB output instead.

Why does the page refuse my .m2ts file?

The accepted-extension list here is .mts only. AVCHD travels under two names: cameras write .mts on the card, while Windows, Blu-ray tools, and various import utilities write .m2ts containing what is usually the same transport stream byte for byte. Rename the file to .mts, or use M2TS to MPEG, which accepts the other spelling.

What is the practical limit on file size, and what happens to my upload?

There is no fixed per-file cap; upload size and connection speed are what limit you in practice. AVCHD allows up to 24 Mbps, so an hour of 1080p footage is several gigabytes before the conversion even starts — cutting the section you need first with Video Cutter is usually the faster route. Whatever you upload travels over an encrypted connection, is processed on our servers, and is deleted automatically a few hours after the job finishes. Nothing is shared or made public, and there is no sign-up or watermark.