M2TS to AVI Converter

M2TS to AVI — Which One Should Your Footage End Up In?

M2TS is the BDAV MPEG-2 transport stream that Blu-ray Discs and AVCHD camcorders write: H.264/AVC video with Dolby Digital (AC-3) or linear PCM audio, carried in 192-byte transport packets (the standard 188-byte MPEG-2 TS packet plus a 4-byte timing header). AVI is Microsoft's RIFF container, introduced on 10 November 1992 as part of Video for Windows — fourteen years older than the AVCHD specification Sony and Panasonic launched in 2006. Converting one into the other is a deliberate step backwards in efficiency, and it is the right call in exactly one situation: a legacy Windows editor, capture tool, or set-top player that reads AVI and refuses anything newer. If that is not your situation, convert M2TS to MP4 instead.

M2TS Source vs AVI Output, Side by Side

When AVI Is the Right Target

• A legacy Windows editing or capture tool — the VirtualDub generation and the NLEs built around it — lists AVI as its only reliable import.
• A set-top or in-car player whose manual names AVI, DivX, or Xvid but says nothing about MP4 or AVCHD.
• A script or batch pipeline already built around AVI that you cannot change, where matching the existing format matters more than file size.
• You need an uncompressed or lossless intermediate: the codec list here includes HuffYUV, which throws away nothing but produces very large files.

When to Skip AVI

• Anything made in the last decade — phones, smart TVs, tablets, browsers, current editors — reads MP4 more dependably than AVI. Use M2TS to MP4.
• You only want a smaller file at the same resolution. AVI's default MPEG-4 Part 2 codec is a generation behind the H.264 already inside your M2TS, so matching the source's look costs more bits, not fewer. Compress M2TS keeps the efficient codec.
• You need 5.1 surround to survive intact and be recognised everywhere — MKV and MP4 handle multichannel audio far more predictably than AVI.

How to Convert M2TS to AVI

1. Upload Your M2TS File: Drag your .m2ts clip onto the page or click "+ Add Files". This page accepts the .m2ts spelling only; camcorder cards that write .MTS have their own page at MTS to AVI. Queue several clips to run them through the same settings.
2. Choose Video Codec and Audio Codec: AVI output starts on the MPEG-4 video codec with MP3 audio — the pairing legacy AVI software expects. Xvid, DivX, and MS MPEG-4 sit alongside it for players that name those specifically, and H.264, H.265, MPEG-2, MJPEG, and HuffYUV are all in the same dropdown if your target is fussier.
3. Set File Compression, Video Resolution, or Trim: Under File Compression, Quality Preset starts on Very High (Recommended); Specific file size, Constant Bitrate, Variable Bitrate, Constant Quality, and Constraint Quality are the alternatives. Video resolution starts on Keep original and offers presets from 4320p down to 144p, a percentage, or an exact Width x Height. Trim → Time Range takes a start time and a duration in seconds or HH:MM:SS.sss.
4. Convert and Download: Click "Convert" and save the AVI. Files upload over an encrypted connection, are processed on our servers, and are deleted automatically after a few hours — no sign-up, no watermark.

Rate Control: What Each File Compression Mode Actually Does

On the MPEG-4 family — MPEG-4, DivX, Xvid, MS MPEG-4, MPEG-1, H.263, WMV — that "CRF" box is not an x264-style CRF at all. We hand it to the encoder as a quantizer scale from 1 to 31, where 1 is the best quality and the largest file, because that is the only quality dial those encoders have. Values that feel right for H.264 will look very wrong here: 23 on this scale is near the bottom of the range, not the middle.

Frequently Asked Questions

Will converting M2TS to AVI lose quality?

Yes, some — the conversion cannot be lossless. Every job here is a real re-encode, not a container rewrap, so the H.264 picture in your M2TS is decoded and encoded again into whichever AVI codec you chose. With the default MPEG-4 Part 2 that is also a step down a codec generation, so fine detail, grain, and gradients take a visible hit at ordinary bitrates. Keep Quality Preset on Very High, leave Video resolution on Keep original, and keep the original M2TS as your master. If a single clean generation matters more than the AVI extension, M2TS to MP4 keeps you on the H.264 side of the fence.

Why is my AVI bigger than the M2TS it came from?

Because you moved from a newer codec to an older one and asked it to hold the same picture. H.264 in your M2TS needs roughly half the bits that MPEG-4 Part 2, Xvid, or DivX need for a comparable result, so matching the source's look costs more, not less. AVI's own container overhead adds to it — roughly 5 MB of index and chunk data per hour of standard-definition video, since every frame is its own indexed chunk. If the file has to shrink, drop Video resolution to a 720p or 480p preset, set a Specific file size target, or stay on H.264 with Compress M2TS.

Which codec should I pick for an old Windows editor?

Start with the default MPEG-4 plus MP3 — that is the combination AVI-era software was written around, and it is what most legacy editors will accept without a codec pack. If the program's documentation names Xvid or DivX specifically, switch to it; they share the same MPEG-4 Part 2 decoding core, so a tool that reads one usually reads the other. MS MPEG-4 is the right pick only for something genuinely old that expects Microsoft's own variant. Reach for HuffYUV if you need a lossless intermediate to edit against, and be ready for a very large file.

My camcorder files are named .MTS — will they upload here?

Not on this page. .MTS and .m2ts are the same BDAV transport stream — the camcorder writes the short 8.3-style .MTS name to the card, and the same clip usually arrives as .m2ts once it is copied to a computer — but this converter accepts the .m2ts extension only. Camcorder-named footage goes to MTS to AVI, which performs the identical conversion. Renaming the file from .MTS to .m2ts also works, because the bytes inside are unchanged.

Why does my converted footage still show comb lines on motion?

Because the recording itself is interlaced and nothing in this pipeline changes that. AVCHD specifies 60i and 50i modes, and a great many consumer camcorders shipped with 1080i as the factory setting. An interlaced frame is woven from two fields captured a fraction of a second apart, so anything that moved between them shows comb teeth on a progressive screen. There is no deinterlacing step anywhere in this converter, and no preset, codec, or intermediate format will add one — converting to MP4 first does not fix it either. The combing is baked into the frames you started with. If it bothers you, deinterlace in a desktop editor (yadif, QTGMC, or your NLE's own field filter) and convert that progressive export instead.

My 1440×1080 AVCHD clip came out looking squashed — what happened?

You hit AVCHD's anamorphic mode. The specification allows 1440×1080 as well as 1920×1080, and the 1440-wide modes store non-square pixels that are meant to be stretched back out to 16:9 on playback. This converter applies no pixel-aspect correction, so once the frame is resized it is treated as square-pixel and the picture ends up horizontally compressed. The fix is to state the geometry yourself: choose Width x Height under Video resolution and enter 1920 × 1080. Clips recorded at a native 1920×1080 are unaffected.

Can I convert M2TS files ripped from a commercial Blu-ray?

Only if they are not copy-protected. Retail Blu-ray titles are encrypted with AACS, often with BD+ on top, and those M2TS streams cannot be read or converted while the protection is in place — no conversion tool can legally strip it. This page handles M2TS files you can already open and play: your own AVCHD camcorder footage, your own renders and recordings, and unprotected discs. If the upload fails or the output is empty, encryption is the first thing to rule out.

What happens to my AC-3 or 5.1 surround audio?

It is re-encoded, and by default it is re-encoded to MP3. AVCHD records Dolby Digital (AC-3) or linear PCM, and the AVI container has no notion of passing either through untouched. MP3 is the safe legacy default but is a stereo-oriented choice, so a 5.1 mix folds down. If you need the surround layout to survive, switch Audio Codec to AC3, EAC3, or DTS (DCA) before converting — all three are in the dropdown, along with AAC, MP2, FLAC, Vorbis, Speex, WMA, and 16/24/32-bit PCM. Be aware that a multichannel AVI is exactly the kind of file older players handle inconsistently.

Can I convert only part of a long recording, and how are my files handled?

Yes — open Trim, switch it to Time Range, and give it a start time and a duration, either in plain seconds or as HH:MM:SS.sss. That runs in the same pass as the conversion, so a 40-minute camcorder take can become a 90-second AVI without a second job. For heavier cutting across several segments, Video Cutter takes .m2ts directly. Whichever route you use, your file is 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. The practical ceiling is upload size and time rather than a fixed cap, and HD camcorder footage is bulky, so a long take spends most of its wall-clock time uploading.