MTS to AVI Converter

Convert MTS to AVI: What This Tutorial Covers

This walk-through is for anyone with .MTS clips from a Sony or Panasonic AVCHD camcorder that need to land in an .AVI container — usually to feed an older Windows editor or a legacy player that refuses to open AVCHD. It explains which codec and quality settings to pick, why this is a full re-encode rather than a quick remux, and when you should reach for MP4 instead.

A quick reality check first: AVI is a Microsoft container from November 1992, and it is showing its age. It has no native, spec-compliant support for H.265/HEVC (the original AVI design excludes the B-frames modern codecs rely on), it cannot reliably hold some variable-bitrate audio, and it carries no subtitles, attachments, or standardized aspect-ratio metadata. If your goal is a small, modern, widely playable file, convert MTS to MP4 instead — AVI only makes sense when a specific old tool or device demands the .avi extension.

How to Convert MTS to AVI

1. Upload Your MTS File: Drag and drop your .MTS clip onto the page or click "+ Add Files" to browse. You can queue several camcorder clips at once; they convert with the same settings.
2. Pick a Video Codec: Expand "Show All Options" and choose the AVI video codec. H.264 keeps files smallest at a given quality; choose MPEG-4 (Xvid/DivX) or Motion JPEG only if your target editor or player specifically needs one of those classic codecs.
3. Set Quality and Resolution (Optional): Use the Quality Preset (the "Very High" preset is the default) to trade size against fidelity, and "Video resolution" to keep the original 1080 frame or downscale. You can also Trim to export only the part of the clip you need.
4. Convert and Download: Click "Convert" and download the .AVI file. No sign-up, no watermark.

Walk-through: Choosing the Right Codec and Quality

Because AVI cannot simply carry the AVCHD bitstream untouched, the H.264 video and AC-3/PCM audio inside your MTS file are decoded and re-encoded into the AVI container. That is a re-encode, not a lossless copy, so the right settings matter — a too-aggressive quality setting will visibly soften the picture.

• If you just want broad playback in old software: leave the video codec on H.264 and the Quality Preset on "Very High." This is the smallest modern-friendly option AVI can hold.
• If your target tool is a classic Xvid/DivX-era editor: pick the MPEG-4 (Xvid/DivX) codec so the file opens without extra codec packs.
• If you need frame-accurate editing in a legacy NLE: Motion JPEG (MJPEG) encodes each frame independently, which some older editors scrub more smoothly — at the cost of a much larger file.
• If file size matters: drop the Quality Preset one step (to "High") and downscale "Video resolution" from 1080 to 720 rather than crushing quality at full resolution.

For audio, MP3 and AC-3 are the safest choices for an AVI that needs to open in old players; uncompressed PCM is an option when you want to avoid any further audio re-encoding loss but do not mind the larger size.

Common Errors and How to Fix Them

• "The video shows comb-like horizontal lines on motion" — Many AVCHD camcorders record 1080i (interlaced). On fast movement the two interleaved fields land in slightly different places, which reads as combing. If your editor offers a deinterlace filter on import, apply it there; otherwise convert MTS to MP4 and deinterlace in a modern player or editor.
• "My old editor still won't open the AVI" — It likely lacks the codec inside the container. Re-export with the MPEG-4 (Xvid/DivX) video codec and MP3 audio, the combination classic Windows tools are most likely to decode without extra codec packs.
• "The AVI file is huge" — AVI compresses less efficiently than modern containers, and Motion JPEG especially balloons file size. Switch the codec to H.264, lower the Quality Preset, or downscale the resolution. To keep the camcorder format but shrink it, compress MTS directly.
• "Audio is out of sync or silent" — Some players mishandle AC-3 inside AVI. Re-export with MP3 audio, which AVI carries most reliably.

When This Doesn't Work

AVI is the wrong destination more often than not in 2026. If you only need the footage to play on a phone, modern TV, web page, or current editing app, MP4 with H.264 is smaller, streams properly, and is supported far more widely — go straight to convert MTS to MP4. If you already have an AVI that a newer tool rejects, the fix is usually the same in reverse: convert AVI to MP4. Reach for AVI only when a specific legacy application or device explicitly requires the .avi extension. Damaged or partially copied MTS files (a frequent result of pulling clips off a camcorder's AVCHD folder structure incorrectly) may fail to convert at all; re-copy the original .MTS from the camera's stream directory before trying again.

Frequently Asked Questions

Does converting MTS to AVI lose quality?

Yes, to some degree — it is a re-encode, not a remux. The H.264 stream inside MTS is decoded and re-encoded into AVI, so picture quality depends on the codec and Quality Preset you pick. In our testing, keeping the video codec on H.264 at the "Very High" preset and leaving the resolution at the original 1080 keeps the loss visually minor; aggressive presets or downscaling are where quality drops become obvious.

Why is my AVI larger than the original MTS file?

AVI compresses less efficiently than the AVCHD container, and some AVI codecs make it worse. Motion JPEG stores every frame as a separate image, so it can be several times larger than the source. For the smallest AVI, use the H.264 video codec; if size still matters, lower the Quality Preset or downscale the resolution.

Should I convert MTS to AVI or to MP4?

For almost any modern use — phones, smart TVs, web upload, current editing apps — MP4 is the better choice. AVI is a 1992 Microsoft container that lacks proper support for H.265, modern streaming, and metadata. Pick AVI only when a specific older Windows editor, player, or device requires the .avi extension; otherwise convert MTS to MP4.

Can AVI hold H.265/HEVC video from my camcorder?

No. AVCHD records H.264, and AVI's original specification cannot properly carry codecs such as H.265 that depend on B-frames referencing future frames. This converter outputs older AVI-compatible codecs (H.264, MPEG-4/Xvid/DivX, Motion JPEG) precisely because they fit what the AVI container was designed to hold.

My converted video has jagged horizontal lines — what happened?

That is interlacing. Many AVCHD camcorders capture 1080i, dividing each frame into two fields; fast motion makes those fields visibly disagree, producing a comb pattern. Deinterlace it in your editor on import, or convert MTS to MP4 and deinterlace in a modern player, which generally handles AVCHD interlacing better than legacy AVI workflows.

Are my uploaded files kept private?

Files are uploaded over an encrypted connection, processed on our servers, and deleted automatically a few hours after conversion — no sign-up, no watermark, and your files are never shared or made public.