Convert M2TS to ALAC — Free Online Tool
Extract and convert audio from M2TS Blu-ray or AVCHD files into ALAC, Apple's lossless audio format stored in an M4A container. This tool decodes the original AAC, AC-3, DTS, or PCM audio track from your M2TS file and re-encodes it with bit-perfect ALAC compression — preserving every detail of the source audio with no quality loss.
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FFmpeg Command
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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 is a MPEG-2 Transport Stream container typically carrying video alongside one or more audio tracks encoded in formats like AAC, AC-3 (Dolby Digital), DTS, or PCM — common on Blu-ray discs and AVCHD camcorders. This conversion strips the video stream entirely and transcodes the first audio track into ALAC (Apple Lossless Audio Codec), which uses lossless compression to reproduce the source audio sample-for-sample. Because the source audio codec (e.g., AC-3 or AAC) is not the same as ALAC, a full decode-and-re-encode is performed rather than a simple stream copy. The resulting M4A file is an MPEG-4 container holding a single ALAC audio stream — compatible with iTunes, Apple Music, and the broader Apple ecosystem. No video data is written to the output.
What Each Flag Does
| Flag | What it does |
|---|---|
ffmpeg
|
Invokes the FFmpeg tool, which handles all demuxing, decoding, encoding, and muxing operations for this conversion. |
-i input.m2ts
|
Specifies the input file — an M2TS container, typically from a Blu-ray disc rip or AVCHD camcorder, which may contain video, multiple audio tracks, and subtitle streams. |
-c:a alac
|
Instructs FFmpeg to encode the audio stream using the ALAC (Apple Lossless Audio Codec) encoder, producing lossless audio output that is fully compatible with iTunes, Apple Music, and Apple devices. This flag appears twice in the resolved command, which is redundant but harmless — the second instance overrides the first with the same value. |
output.m4a
|
Defines the output file as an M4A file — an MPEG-4 audio container, which is the standard and required wrapper for ALAC audio. The .m4a extension signals to FFmpeg to mux the ALAC stream into an MPEG-4 container, and ensures compatibility with Apple ecosystem applications. |
Common Use Cases
- Ripping the lossless or high-quality audio soundtrack from a Blu-ray disc backup (M2TS file) to archive it in Apple's lossless format for long-term storage.
- Importing concert or live-performance footage recorded with an AVCHD camcorder and extracting the audio as ALAC for editing in Logic Pro or GarageBand.
- Preserving the audio from a high-definition broadcast recording saved as M2TS before the video is discarded, keeping a lossless master for future use.
- Converting Blu-ray audio tracks to ALAC for playback on an iPhone, iPad, or Apple TV via the Apple Music library, which natively supports ALAC.
- Archiving the audio commentary or alternate audio track from a Blu-ray M2TS file in a lossless format before transcoding the main file to a smaller format.
- Extracting clean, uncompressed-quality audio from an AVCHD camcorder clip to use as a reference sync track during professional video post-production.
Frequently Asked Questions
That depends on what audio codec is in your M2TS file. If the source contains lossless audio such as Dolby TrueHD or uncompressed PCM, the resulting ALAC file will be a lossless representation of that audio — no quality is lost. If the source uses a lossy codec like AC-3 (Dolby Digital) or AAC, those compression artifacts are already baked into the audio; ALAC will preserve that audio faithfully but cannot recover information that was discarded by the original lossy encoding.
ALAC is always stored inside an MPEG-4 container, which uses the .m4a file extension for audio-only files. This is by design — Apple developed ALAC specifically for the MPEG-4 container ecosystem. The M4A format is recognized natively by iTunes, Apple Music, QuickTime, and all Apple devices. If you need the audio in a different lossless format like FLAC or WAV, you would need a separate conversion tool.
No. ALAC inside an M4A container supports only a single audio track, whereas M2TS files often carry multiple audio tracks (e.g., a main feature soundtrack plus a director's commentary). This conversion extracts only the first audio track found in the M2TS file. If you need a specific alternate track — such as a DTS-HD or secondary language track — you would need to use FFmpeg's -map flag on the command line to select the desired stream by its index.
Both the video stream and any subtitle streams are discarded. ALAC/M4A is a pure audio format with no support for video or subtitle data. The output file will contain only the audio. If you need to retain subtitles or video, you should use a video output format instead of ALAC.
M2TS files often contain multiple audio streams. To select a specific one, add a -map flag before the output filename. For example, to extract the second audio stream (zero-indexed as 0:a:1), the command becomes: ffmpeg -i input.m2ts -map 0:a:1 -c:a alac output.m4a. You can first run ffmpeg -i input.m2ts (with no output file) to list all streams and identify the index of the audio track you want.
If the source M2TS carries lossless PCM audio, the ALAC output will typically be 40–60% smaller than the raw PCM data because ALAC uses lossless compression similar to FLAC. If the source carries lossy AC-3 or AAC audio, the ALAC file will likely be larger than the original audio stream, since ALAC losslessly encodes the decoded PCM samples rather than storing the compact lossy bitstream. In both cases, the audio content is preserved exactly.
Technical Notes
M2TS files used on Blu-ray discs commonly carry audio in formats such as Dolby TrueHD, DTS-HD Master Audio, LPCM, AC-3, or AAC. FFmpeg will decode whichever audio codec is present and re-encode it to ALAC. The ALAC encoder in FFmpeg (codec identifier: alac) produces output that is fully compliant with Apple's specification and bit-for-bit identical upon decoding. ALAC does not support a variable bitrate quality setting — it is inherently lossless, so there are no audio quality parameters to tune. Metadata tags from the M2TS source (such as title or track information) are generally not present in M2TS transport streams and will not carry over to the M4A file. Chapter markers from the M2TS file are not preserved in this conversion. If the M2TS file has multiple audio channels (e.g., 5.1 surround), ALAC fully supports multi-channel audio up to 8 channels, so the channel layout will be preserved in the output M4A file.