Extract Audio from M2TS to AAC — Free Online Tool
Extract audio from M2TS Blu-ray and AVCHD files and save it as AAC — a modern lossy format ideal for streaming, mobile playback, and iTunes compatibility. This tool strips the video stream entirely and re-encodes the audio track (commonly Dolby TrueHD, DTS-HD, or AC-3 in Blu-ray sources) into standard AAC at your chosen bitrate.
to
FFmpeg Command
Copy this command to run the same conversion locally with FFmpeg on your desktop. Download FFmpeg
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Note: Browser-based encoding uses approximate quality targets. For precise CRF compression, copy the FFmpeg command above and run it on your desktop.
Estimated output:
Conversion Complete!
DownloadHow It Works
M2TS files from Blu-ray discs or AVCHD camcorders typically carry high-bitrate audio codecs such as Dolby TrueHD, DTS-HD Master Audio, AC-3, or PCM — none of which can be placed natively into a raw AAC file. This conversion discards the video stream entirely using the -vn flag, then decodes whichever audio codec is present in the M2TS and re-encodes it into AAC using FFmpeg's built-in AAC encoder. Because M2TS files often contain multiple audio tracks (e.g., a primary language track and a director's commentary), FFmpeg will select the default audio stream by default. The result is a compact, widely compatible .aac file ready for use on Apple devices, streaming platforms, or any HTML5-capable media player.
What Each Flag Does
| Flag | What it does |
|---|---|
ffmpeg
|
Invokes the FFmpeg binary. In the browser-based version of this tool, this runs via FFmpeg.wasm compiled to WebAssembly — no files leave your device. On a desktop, this calls your locally installed FFmpeg executable. |
-i input.m2ts
|
Specifies the input M2TS file — a Blu-ray BDAV or AVCHD container that may contain multiple video streams, audio tracks in formats like TrueHD or AC-3, and subtitle streams. FFmpeg reads and demuxes all streams from this container before processing begins. |
-vn
|
Disables video output entirely — critical for this audio extraction use case. Without this flag, FFmpeg would attempt to include or process the H.264/H.265 video stream from the M2TS, which is unnecessary overhead since we only want the audio. |
-c:a aac
|
Specifies the AAC encoder for the audio stream. FFmpeg decodes whatever audio codec is present in the M2TS (TrueHD, DTS-HD, AC-3, PCM, etc.) and re-encodes it as AAC using FFmpeg's built-in native AAC encoder, which produces standards-compliant output compatible with Apple devices, browsers, and streaming platforms. |
-b:a 128k
|
Sets the AAC audio bitrate to 128 kilobits per second, the default for this tool. For Blu-ray source material this represents a significant reduction from the original bitrate but produces audio that is acceptable for most listening contexts. Increase to 192k or 256k to better preserve the fidelity of high-quality Blu-ray audio sources. |
output.aac
|
The output filename. The .aac extension tells FFmpeg to write a raw AAC elementary stream without any container wrapper. If you rename this to output.m4a, FFmpeg will instead wrap the AAC audio in an MPEG-4 container, which is preferable for iTunes compatibility and better metadata support. |
Common Use Cases
- Ripping the audio score or soundtrack from a Blu-ray disc rip to keep as a standalone music file without storing gigabytes of video
- Extracting dialogue or narration from an AVCHD camcorder recording to use in a video editing project that needs a lightweight audio-only clip
- Converting Blu-ray concert recordings to AAC for syncing to an iPhone or iPod via iTunes, since AAC is Apple's preferred audio format
- Pulling the audio from a Blu-ray documentary to create a podcast episode or audio lecture, reducing file size dramatically compared to the original M2TS
- Archiving just the audio from home video AVCHD recordings when the video has already been edited and only the audio reference track needs to be retained
- Preparing an AAC audio file from a Blu-ray source for upload to a streaming platform or content delivery network that requires AAC-encoded audio
Frequently Asked Questions
Yes — this is a lossy conversion in nearly all cases. Blu-ray M2TS files frequently carry lossless or near-lossless audio formats like Dolby TrueHD or DTS-HD Master Audio, both of which are decoded and then re-encoded into AAC, which is a lossy format. At the default 128k bitrate most listeners find the result acceptable for casual use, but audiophiles preserving lossless Blu-ray audio should consider exporting to FLAC instead. If the source M2TS uses AC-3 (Dolby Digital), you are also undergoing a decode-then-re-encode cycle, which introduces some generation loss.
By default, FFmpeg selects the first audio stream flagged as default in the M2TS container, which is typically the primary language track. If you need a specific track — for example, a director's commentary or a Dolby Atmos object-based track — you can modify the command to add '-map 0:a:1' (for the second audio stream) before the output filename. Since raw AAC files do not support multiple audio tracks, each track would need to be extracted as a separate file.
Replace '128k' in the '-b:a 128k' portion of the command with your desired bitrate. For Blu-ray source material where you want good fidelity, '192k' or '256k' are reasonable choices — AAC at 192k is broadly considered transparent (indistinguishable from the source for most listeners). Going above 256k yields diminishing returns for AAC. The full command at 256k would be: ffmpeg -i input.m2ts -vn -c:a aac -b:a 256k output.aac
The single-file command shown here processes one file at a time, but on a desktop you can wrap it in a shell loop. On Linux or macOS: 'for f in *.m2ts; do ffmpeg -i "$f" -vn -c:a aac -b:a 128k "${f%.m2ts}.aac"; done'. On Windows PowerShell: 'Get-ChildItem *.m2ts | ForEach-Object { ffmpeg -i $_.FullName -vn -c:a aac -b:a 128k ($_.BaseName + ".aac") }'. This is especially useful for ripping audio from a full Blu-ray disc rip split into multiple M2TS segments.
The command outputs a raw AAC bitstream (.aac), which is an elementary stream without a container wrapper. An .m4a file is AAC audio wrapped in an MPEG-4 container, which adds better metadata support (title, artist, album art) and broader seeking compatibility. For iTunes or Apple Music compatibility, you may prefer .m4a — you can achieve this by changing the output filename in the command to 'output.m4a', which prompts FFmpeg to wrap the AAC stream in an MP4 container automatically. Both files contain identical AAC audio; only the wrapper differs.
The size reduction is substantial. A typical Blu-ray M2TS file runs at 25–40 Mbps total bitrate, with video accounting for the vast majority. A Dolby TrueHD audio track alone might be 3–5 Mbps. Re-encoding that to AAC at 128k brings the audio down to 0.128 Mbps, so a 2-hour Blu-ray rip producing roughly 20GB as M2TS would yield an AAC file of only about 110–130 MB. Even at 320k, the resulting AAC file would be under 300MB for the same content.
Technical Notes
M2TS uses an MPEG-2 Transport Stream wrapper with a 192-byte packet structure (extended from the standard 188-byte TS packet with a 4-byte timestamp prefix for Blu-ray). The audio codecs you encounter inside M2TS vary significantly depending on the source: Blu-ray discs commonly carry Dolby TrueHD, DTS-HD Master Audio, or AC-3; AVCHD camcorders typically use AC-3 or linear PCM. FFmpeg decodes all of these transparently before passing the audio to the AAC encoder. One important limitation: M2TS files with Dolby Atmos (carried as a TrueHD extension) will have the object-based spatial metadata discarded during decoding — the output AAC will contain only the standard stereo or 5.1 Dolby TrueHD core. If the M2TS contains a multichannel audio track (e.g., 5.1 surround), FFmpeg's AAC encoder will encode all channels by default; the result will be a multichannel AAC file, which most players support but raw .aac container support can be inconsistent — wrapping in .m4a is safer for surround content. Metadata such as chapter markers and subtitle tracks present in the M2TS are not preserved in the AAC output, as the AAC elementary stream format supports neither.