AVCHD to MKV Converter

Convert AVCHD to MKV: What This Tutorial Covers

AVCHD is the high-definition camcorder format Sony and Panasonic introduced in 2006 — H.264/AVC video paired with Dolby AC-3 or Linear PCM audio, multiplexed into an MPEG transport stream and stored on the card under PRIVATE/AVCHD/BDMV/STREAM/ as .MTS clips. This converter rewraps that footage into MKV (Matroska), the open container that the Matroska project began building in December 2002 and that the IETF standardized as RFC 9559 in October 2024. This walk-through is for anyone rescuing a camcorder archive into a future-proof, vendor-neutral container before the original cards or tapes degrade — and it explains plainly what happens to your video and audio in the process, because this is a re-encode, not a lossless copy.

How to Convert AVCHD to MKV

1. Upload Your AVCHD File: Drag and drop your camcorder clip onto the page or click "+ Add Files". Add several clips to archive them in one batch with the same settings.
2. Set the Quality Preset: Open Advanced Options and pick a Preset — "Very High (Recommended)" is the default and is the right choice for archiving, since it keeps the re-encoded picture close to the source. You can switch File Compression to "Specific file size" or a Variable/Constant Bitrate if you need to hit a storage target instead.
3. Adjust Video resolution or Trim (optional): Leave Video resolution on "Keep original" to preserve the camera's native frame size, or scale it down to save space. Use Trim to keep only part of a clip before converting.
4. Convert and Download: Click "Convert" and download your MKV file. No sign-up, no watermark.

Walk-through: This Is a Re-encode, Not a Container Swap

The single most important thing to understand about AVCHD to MKV here is that the video is re-encoded, not copied. Both AVCHD and the MKV this tool produces use H.264 by default (you can see "H.264" preselected under Video Codec in Advanced Options), so it is tempting to assume the footage is simply lifted out of the transport stream and dropped into Matroska untouched. It is not — the clip is decoded and re-encoded as it passes through the pipeline. That means the result is one generation removed from the camera original: at the default "Very High" preset the difference is hard to see, but quality can only stay the same or drop slightly, never improve.

• Want the closest match to the camera original: leave the Preset on "Very High (Recommended)" and Video resolution on "Keep original". This is the archival setting.
• Want a smaller archive file: switch File Compression to "Specific file size" and enter a target, or drop the Preset a notch — accept that you trade some picture detail for size.
• Want to hit an exact storage budget: use "Constant Bitrate" or "Variable Bitrate" and set the rate directly.
• Want only part of a long clip: use Trim to set a start point and duration so you archive just the segment you care about.

A word on the audio: AVCHD camcorders record sound as Dolby AC-3 (Dolby Digital) — the common choice, picked so footage stays compatible with Blu-ray authoring — or as uncompressed Linear PCM on some professional models. The default audio codec for the MKV output is AAC, so an AC-3 track is re-encoded from one lossy format to another, which adds a small amount of generational loss. If you would rather keep the audio bit-for-bit, MKV can also carry FLAC or PCM losslessly; pick one of those under Audio Codec in Advanced Options when the soundtrack matters more than file size.

Common Errors and How to Fix Them

• "My MKV doesn't look sharper than the original" — Expected. This is a re-encode of already-compressed H.264, so the output can match the source but never exceed it. Use the "Very High" preset to keep the difference negligible.
• "The motion looks combed or has horizontal lines" — Older AVCHD footage is often interlaced (1080i). If your clip was shot interlaced, fine horizontal lines can appear on progressive screens; deinterlacing in a dedicated editor before or after conversion usually cleans this up. Footage shot in AVCHD Progressive (720p, or 1080p on 2011-and-later cameras) is not affected.
• "The file is too large to upload" — AVCHD clips carry full HD video and can be large; a long recording may take a while to upload over your connection. Trim the clip first, or convert a few at a time rather than a whole card at once.
• "My player won't open the MKV" — VLC, MPV, Kodi, and most modern media players handle MKV well, but some smart TVs and older hardware players don't. If a specific device chokes on Matroska, convert AVCHD to MP4 instead — MP4 is the broader device-compatibility pick.

When This Doesn't Work

If the AVCHD clip is partially corrupted — a common result of pulling the card before the camcorder finished writing — the stream may be unreadable even when a player can still scrub part of the picture. Spanned clips that a camcorder split across multiple .MTS files at the 2 GB or 4 GB mark may also need to be rejoined in the camera's own software before they convert cleanly. And because .avchd clips belong to the same MTS/M2TS camcorder family, the MTS to MKV converter does the identical job if your footage carries the .mts extension instead. For a quick re-wrap of many other formats into MKV, the general video converter covers the wider set.

Frequently Asked Questions

Is converting AVCHD to MKV lossless, or does it re-encode the video?

It re-encodes. Even though both AVCHD and this MKV output use H.264, the footage is decoded and re-encoded as it passes through the converter rather than copied stream-for-stream, so the result is one generation removed from the camera original. At the "Very High" preset the loss is minimal and hard to spot, but the output can only match the source quality, not improve on it.

Why archive camcorder footage as MKV instead of leaving it as AVCHD?

MKV (Matroska) is an open, royalty-free container standardized by the IETF as RFC 9559, so it isn't tied to a camcorder's proprietary folder structure and is read by a wide range of players and editors. AVCHD clips normally live as .MTS files buried under PRIVATE/AVCHD/BDMV/STREAM/, which is awkward to back up and easy to break if the folder tree is disturbed. A single self-contained .mkv per clip is far simpler to store, label, and migrate forward as hardware changes.

What audio codec ends up in the MKV?

By default the audio is re-encoded to AAC. AVCHD camcorders usually record Dolby AC-3, which is already lossy, so AC-3 to AAC is a lossy-to-lossy re-encode that adds slight generational loss — encode at a bitrate matching or exceeding the source to keep it minimal. If you want to preserve the soundtrack exactly, MKV can carry FLAC or PCM losslessly; select one of those under Audio Codec in Advanced Options.

Will the MKV keep multiple audio tracks or subtitles from the original?

MKV as a container fully supports multiple audio tracks, subtitles, and chapters, which is a large part of why it is favored for archiving. A typical single AVCHD camcorder clip, however, carries just one audio track and no subtitle stream, so there is usually only one track to carry over. The benefit of MKV here is future headroom — you can add alternate audio or subtitle tracks to the archived file later.

Is a .avchd file the same thing as an MTS or M2TS file?

They're the same family. AVCHD is the recording format; the actual clips are usually .MTS files stored under PRIVATE/AVCHD/BDMV/STREAM/ on the camcorder (.m2ts once copied to a computer or Blu-ray). A file simply named .avchd is camcorder footage from that structure, so it carries the same H.264 video and AC-3 or LPCM audio. The conversion is identical whether your clip ends in .avchd, .mts, or .m2ts.

How are my files handled, and is there a size limit?

Your AVCHD file is uploaded over an encrypted connection, processed on our servers, and deleted automatically a few hours after conversion — no sign-up, no watermark, never shared or made public. In our testing, the main practical limit is upload size and time rather than the conversion itself: AVCHD clips carry full HD video and can be large, so a long recording may take a while to upload even though the conversion that follows is quick.