MTS to AIFC Converter

Extract AIFC Audio from MTS: What This Tutorial Covers

This converter pulls the audio track out of an MTS (AVCHD) camcorder clip and saves just the sound as an AIFC (AIFF-C) file — the H.264 video is discarded and you keep only the soundtrack. It is aimed at one specific situation: getting camcorder audio into an older Mac, a classic Logic Pro or Pro Tools-era session, or a hardware sampler that imports AIFF-family files but won't touch a raw video container. This walk-through shows where the .MTS clip hides on the memory card, what happens to the audio depending on how your camera recorded it, why the AIFC comes out large, and the one real gotcha — a slight length drift from AC-3's decode padding — that trips people up in an editor.

How to Convert MTS to AIFC

1. Upload Your MTS File: Drag and drop your .MTS (or .M2TS) clip onto the page, or click "+ Add Files" to browse. Queue several clips to extract them in one batch with the same settings.
2. Leave the Audio Codec on the AIFC Default: Under "Show All Options," the Audio Codec defaults to PCM 16-bit Big Endian — standard uncompressed audio inside the AIFC container, which is what older Mac editors and samplers expect. You can switch to PCM A-law / mu-law for a smaller telephony-style file, but plain PCM is the safe, importable choice.
3. Set Audio Channel, Audio Sample Rate, or Trim (Optional): Audio Channel and Audio Sample Rate both sit on Original, copying the source layout — leave them unless your project needs a specific rate, or set Audio Channel to mono/stereo to control how a surround track folds down. Use Trim to keep only part of a long recording.
4. Convert and Download: Click "Convert" and save your .aifc file individually or as a ZIP. No sign-up, no watermark.

Walk-through: Finding the Right File, and What Happens to the Audio

MTS is the AVCHD camcorder format — the codec system Sony and Panasonic introduced in 2006 — and on the card it is a folder structure, not a single file. Footage lives under PRIVATE/AVCHD/BDMV/STREAM/, where each recording is a .MTS clip (the extension becomes .M2TS once the clip is copied to a computer; the bytes are the same BDAV MPEG-2 Transport Stream). This tool takes the individual stream file, so browse into that STREAM/ directory and upload the actual .MTS clip rather than the top-level AVCHD folder.

What happens to the sound depends entirely on how your camcorder recorded it. The AVCHD specification allows two audio types, and they behave very differently here:

• Dolby AC-3 (Dolby Digital) source — the common case. Most consumer AVCHD camcorders record AC-3, which is already a lossy format (up to 5.1 channels). Decoding it to uncompressed PCM inside the AIFC adds no new generation of loss — but it also cannot rebuild detail the AC-3 encode already discarded. You get a clean, editor-ready copy of exactly the quality the source had, not an upgrade.
• Linear PCM source — some professional models. A few pro camcorders record uncompressed Linear PCM. Because that source is already lossless, writing it into a PCM AIFC is a genuinely lossless handoff — camcorder PCM straight to PCM-in-AIFC, with no transcode in between. This is the ideal case; keep Audio Sample Rate on Original so the AIFC inherits the source rate and depth.

Either way, the AIFC is uncompressed, so expect it to be much larger than the clip's audio bitrate suggests — roughly 10 MB per minute for 16-bit/44.1 kHz stereo PCM. That size is the cost of an uncompressed, editor-friendly file:

• Want maximum compatibility with an old DAW or sampler? Keep the default PCM 16-bit Big Endian — it is the most universally readable AIFC payload.
• Need a smaller AIFC for a telephony or speech tool? Switch the Audio Codec to PCM A-law or mu-law, which roughly halves the data rate at the cost of dynamic range.
• Do not expect a bitrate bump to help. There is no "higher quality" setting that recovers what AC-3 compressed away; raising the PCM bit depth only makes the file larger.

Common Errors and How to Fix Them

• "I can't find a file to upload — just folders" — You are looking at the card's PRIVATE/AVCHD/BDMV/ tree. Browse down into STREAM/ and pick the individual .MTS (or .M2TS) clip; that is the file this tool needs.
• "The AIFC is huge compared to the clip's audio" — Expected. PCM is uncompressed, so even a modestly-bitrated AC-3 track becomes about 10 MB per minute as 16-bit stereo PCM. If size matters more than DAW support, extract to MTS to MP3 instead.
• "The audio sounds no better than the original" — Also expected when the source is AC-3. Decoding AC-3 to PCM gives a faithful copy, not added fidelity; only an LPCM source is a truly lossless handoff.
• "The extracted audio is slightly longer than the video / drifts out of sync" — AC-3 (like all lossy audio) carries a few milliseconds of encoder padding, typically around 10–20 ms, and some editors read the camcorder's muxing delay differently. On a single clip this is usually inaudible, but in a tight edit you may need to nudge the track into alignment.
• "My clip has 5.1 surround but I only got stereo" — AVCHD AC-3 can carry up to 5.1 channels; this tool's Audio Channel control offers Original, mono, and stereo, so a surround source is most reliably handled as a stereo fold-down. Use AVCHD to AAC if you need to keep more than two channels.

When This Doesn't Work — and the Simpler Routes

AIFC makes sense for one narrow case: an older Mac, a Logic/Pro Tools-era session, or a hardware sampler that accepts AIFF-family files but rejects a video container. If that is not your situation, a plain WAV is usually the better target — it is the de-facto interchange format for nearly every audio editor on any platform, so MTS to WAV is the more common editing route, and MTS to MP3 is the right pick if you only need the soundtrack to play on a phone, car stereo, or generic player. The conversion can fail outright if the .MTS is partially corrupted — often from pulling the card before the camcorder finished writing — in which case the audio stream may be unreadable even when a player can still scrub the video; re-copy the clip from the card rather than fight a broken file. And if you would rather keep the picture as well as the sound, convert MTS to MP4 re-encodes both streams into one playable file.

Frequently Asked Questions

Does this keep the video, or just the audio?

Just the audio. This is an extraction: the H.264 video inside your MTS clip is discarded and only the soundtrack is written out as an AIFC file. If you want to keep the picture too, convert MTS to MP4 instead, which re-encodes both the video and audio into a single playable file.

Will the AIFC sound better than the audio already in my MTS clip?

It depends on how the camera recorded it, and the honest answer is usually no. Most consumer AVCHD camcorders record Dolby AC-3, which is already lossy — so decoding it to PCM inside an AIFC gives a faithful copy but cannot exceed the source. Some professional models record uncompressed Linear PCM, and that case is different: PCM straight into a PCM AIFC is a genuinely lossless handoff with no transcode at all. Either way you get a clean working copy ready for editing; only the LPCM source starts from true lossless audio.

Why is my AIFC file so much larger than the original soundtrack?

Because this converter writes uncompressed PCM into the AIFC by default. AVCHD audio is compressed (AC-3 packs a stereo track into a few hundred kbps), whereas 16-bit/44.1 kHz stereo PCM runs about 10 MB per minute regardless of the source bitrate. The size jump is the cost of an uncompressed, editor-friendly format, not a setting you can tune away. If you would rather keep things small, extract to a lossy format like MTS to MP3 instead.

Why is my extracted audio slightly longer than the video, and how do I fix the drift?

AC-3, like every lossy audio codec, includes a small amount of encoder padding — typically on the order of 10–20 ms — and different editors interpret the clip's muxing delay differently, so a decoded PCM track can land a hair longer than the original. In our testing this is inaudible on a standalone clip but can show up as a tiny sync offset in a tight multi-clip edit; nudge the audio track into alignment in your DAW if you notice it. An LPCM source avoids the codec-padding part of this entirely.

Can the AIFC keep my MTS clip's 5.1 surround sound?

Not as surround. AVCHD AC-3 audio can carry up to 5.1 channels, but this tool's Audio Channel control offers Original, mono, and stereo, so a surround source is most reliably handled as a stereo fold-down here. If preserving every channel matters, extract to AAC instead, where multichannel is the supported path. For an ordinary recording you will listen to in stereo, the PCM AIFC is exactly what a sampler or DAW wants.

What is AIFC, and is .aifc different from .aiff?

AIFC is AIFF-C, the variant of Apple's Audio Interchange File Format introduced in 1991 to allow compressed payloads inside the same container — though the way this converter writes it, the AIFC holds plain uncompressed PCM. It is part of the same AIFF family that Mac and pro-audio software import natively; .aiff is the classic uncompressed form and .aifc is the cousin that can carry compression. If you only ever need uncompressed audio, plain AIFF works equally well in most tools. To go the other way and squeeze an AIFC back down into an efficient web-ready file, use AIFC to Opus.

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

Your MTS 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. The main practical limit is upload size and time rather than the extraction itself: an MTS clip carries full HD video alongside the audio, so a long recording can take a while to upload even though pulling out the soundtrack is quick.