AVCHD to AAC Converter

Extract AAC Audio from AVCHD: What This Tutorial Covers

This converter pulls the audio track out of AVCHD camcorder footage and saves it as AAC — the video is discarded, you keep only the sound. It's built for anyone lifting interview, event, or ambient audio out of a Sony or Panasonic camcorder clip for a podcast, a music edit, or an audio-only archive. This walk-through shows where the camcorder hides its clips, which file to actually upload, and exactly what happens to the sound depending on how your camera recorded it — because AVCHD ships with two different audio types and the conversion behaves differently for each.

How to Extract AAC from AVCHD

1. Upload Your AVCHD Stream File: Drag and drop your .MTS or .M2TS clip onto the page, or click "+ Add Files". Add several clips to extract them in one batch with the same settings.
2. Set the Quality Preset: Open Advanced Options and pick a Preset under File Compression — the default is fine for most footage, or switch to Custom Bitrate / Constant Bitrate to set the AAC bitrate directly. Match or exceed the source bitrate; encoding higher than the original can't recover detail an AC-3 track already discarded.
3. Set Audio Channel and Sample Rate (optional): Leave Audio Channel and Audio Sample Rate on "Original" to keep what the camera recorded, or set Audio Channel to stereo if your clip carries a 5.1 surround track you want downmixed to two channels. Use Trim to keep only part of a clip.
4. Convert and Download: Click "Convert" and download your AAC file. No sign-up, no watermark.

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

AVCHD is not a single file — on the card it's a folder structure. Sony and Panasonic store footage under PRIVATE/AVCHD/BDMV/STREAM/, where each recording is a .MTS clip (the extension becomes .M2TS once the clip is imported to a computer). This tool takes the stream file, not the whole card folder, so browse into that STREAM/ directory and upload the individual .MTS/.M2TS clip — or a file already labeled .avchd, which holds the same bytes. Uploading the top-level card folder won't work; you need the actual clip inside it.

What happens to the sound depends on how your camcorder recorded it — and AVCHD allows two audio types:

• Dolby AC-3 (Dolby Digital) source — the common case. Most consumer AVCHD camcorders record AC-3, which is already a lossy format. Extracting to AAC is therefore a lossy-to-lossy transcode: the AC-3 is decoded and re-encoded as AAC, which can match the source but never regain detail AC-3 already threw away. Set the AAC bitrate at or above the source rate (AVCHD audio commonly runs at 256 or 384 kbit/s) to keep the second-generation loss minimal.
• Linear PCM source — some professional models. A few pro camcorders record uncompressed LPCM. Because the source is lossless, extracting to AAC is a clean first-generation encode — the same quality you'd get encoding AAC from a WAV master. This is the better-sounding starting point when you have the choice.
• 5.1 surround → stereo: if the clip carries a 5.1 surround track and you want a normal two-channel file, set Audio Channel to stereo and the converter downmixes the six channels to two. Leaving it on "Original" preserves all channels in the AAC output.

AAC (Advanced Audio Coding) is the MPEG/ISO-IEC successor to MP3 and generally sounds better than MP3 at the same bitrate, which is why it's a sensible target for an extracted soundtrack you'll edit or publish.

Common Errors and How to Fix Them

• "I can't find a file to upload — just folders" — You're looking at the card's PRIVATE/AVCHD/BDMV/ tree. Browse down into STREAM/ and pick the individual .MTS (or .M2TS) clip; that's the file this tool needs.
• "The AAC sounds no better than the original" — Expected if your camcorder recorded AC-3. AC-3 is already lossy, so AAC can only match it, not improve it. Encode at a bitrate at or above the source to keep the loss minimal.
• "My clip has surround sound but I want plain stereo" — Set Audio Channel to stereo in Advanced Options to downmix a 5.1 track to two channels before extraction.
• "The file is too large to upload" — AVCHD clips bundle full HD video with the audio, so the upload carries the whole clip even though you only want the sound. A long recording may take a while to upload over your connection; trim or convert a few clips at a time.
• "My clip ends in .avchd, not .mts" — That's the same camcorder footage; the extension is just a label. It extracts identically.

When This Doesn't Work

If the clip is partially corrupted — often from pulling the card before the camcorder finished writing — the audio stream may be unreadable even when a player can still scrub part of the video. Spanned recordings that a camcorder split across multiple .MTS files at the 2 GB or 4 GB mark sometimes need rejoining in the camera's own software first. If you'd rather keep the picture as well as the sound, convert AVCHD to MP4 instead of extracting audio only. And because .avchd, .mts, and .m2ts are the same camcorder family, the direct MTS to AAC and M2TS to AAC routes do the identical extraction when your footage carries those extensions.

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 AVCHD clip is discarded and only the soundtrack is written out as an AAC file. If you want to keep the picture too, convert AVCHD to MP4 instead, which re-encodes both the video and audio into a single playable file.

What audio does AVCHD actually contain, and does that affect the AAC quality?

AVCHD camcorders record one of two audio types. Most consumer models use Dolby AC-3 (Dolby Digital), which is already lossy — so extracting to AAC is a lossy-to-lossy transcode that can match but not exceed the source. Some professional models record uncompressed Linear PCM, which is lossless, so extracting that to AAC is a clean first-generation encode. Either way, set the AAC bitrate at or above the source (AVCHD audio commonly runs 256–384 kbit/s) to keep any second-generation loss minimal.

I only see folders on my camcorder card — which file do I upload?

AVCHD stores clips under PRIVATE/AVCHD/BDMV/STREAM/. Browse into that STREAM/ folder and upload the individual .MTS clip (it's .M2TS once copied to a computer). This tool takes the single stream file, not the whole card folder — uploading the top-level AVCHD directory won't work because it isn't a single media file.

Can it downmix a 5.1 surround track to stereo AAC?

Yes. AVCHD supports both stereo and 5.1 surround. If your clip carries a 5.1 track and you want a standard two-channel file, set Audio Channel to stereo in Advanced Options and the six channels are downmixed to two during extraction. Leave Audio Channel on "Original" to keep every channel in the AAC output.

Should I extract to AAC, or to MP3?

AAC (Advanced Audio Coding) generally sounds better than MP3 at the same bitrate and is the modern default for podcasts, Apple devices, and most editors. Choose AVCHD to MP3 only if a specific tool or workflow requires MP3 for maximum compatibility. For editing or publishing, AAC is the better-quality choice.

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

They're the same camcorder family. AVCHD is the recording format; the actual clips are .MTS files on the camcorder and .M2TS after import. A file named .avchd holds the same H.264 video with AC-3 or LPCM audio, so the audio extraction is identical whether your clip ends in .avchd, .mts, or .m2ts.

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

Your AVCHD clip 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 extraction itself: an AVCHD 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.