Extract Audio from MP4 to ALAC — Free Online Tool
Extract audio from an MP4 video and save it as an ALAC (Apple Lossless Audio Codec) file — a lossless M4A format that preserves every bit of the original audio without any quality loss. ALAC is stored in an MPEG-4 container, making it natively compatible with iTunes, Apple Music, and all Apple devices.
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FFmpeg Command
Copy this command to run the same conversion locally with FFmpeg on your desktop. Download FFmpeg
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Settings
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
This tool reads the audio stream from your MP4 file and re-encodes it using the ALAC codec, outputting a lossless M4A file. Because ALAC uses lossless compression, the resulting audio is mathematically identical to the source — no audio data is discarded. The video stream is completely discarded (using the -vn flag), and the audio is decoded from whatever codec it was stored in within the MP4 (commonly AAC or MP3) and then re-encoded into ALAC. Note that if your source MP4 contained lossy audio like AAC, the ALAC output will be a lossless copy of that lossy audio — existing compression artifacts from the source are preserved, not removed. ALAC itself introduces no additional quality loss.
What Each Flag Does
| Flag | What it does |
|---|---|
ffmpeg
|
Invokes the FFmpeg program — the underlying engine that powers this browser-based tool via WebAssembly. The same binary command can be run in a local terminal on macOS, Windows, or Linux to process files larger than 1GB. |
-i input.mp4
|
Specifies the input file — your source MP4 video. FFmpeg reads both the video and audio streams from this container, though only the audio will be used in the output. |
-vn
|
Stands for 'video none' — this flag tells FFmpeg to discard all video streams from the output. Since ALAC is a pure audio format, no video data is written to the M4A file, keeping the output compact and audio-only. |
-c:a alac
|
Sets the audio codec to ALAC (Apple Lossless Audio Codec). FFmpeg will decode the source audio (typically AAC from the MP4) and re-encode it using lossless ALAC compression, producing an output that is bit-for-bit accurate to the decoded source audio. |
output.m4a
|
The output filename with the .m4a extension — the standard file extension for MPEG-4 audio containers, used by both AAC and ALAC. The .m4a extension ensures Apple devices and iTunes correctly identify the file as an audio-only MPEG-4 file and handle it appropriately in media libraries. |
Common Use Cases
- Importing video-sourced music or concert recordings into an Apple Music library while preserving the best possible audio quality from the source file
- Archiving the audio track from high-quality MP4 recordings — such as studio sessions or live performances — in a lossless format for long-term storage
- Preparing audio from MP4 videos for use in Logic Pro, GarageBand, or other Apple audio software that works natively with ALAC/M4A
- Stripping the audio from MP4 documentary or film rips to study or reference soundtracks and scores without transcoding to a lossy format
- Converting MP4-based audiobook or lecture recordings to ALAC for playback on Apple devices via the Books or Podcasts app with no re-encoding quality penalty
- Creating a lossless master audio file from an MP4 source before further editing or format conversion, to avoid generational quality loss from repeated lossy encodes
Frequently Asked Questions
Not if the source MP4 contained lossy audio, which is the most common case — MP4 files typically use AAC or MP3 audio. ALAC is a lossless codec, meaning it perfectly preserves whatever audio it encodes, but it cannot recover audio data that was already discarded by the original lossy compression. The ALAC file will sound identical to the source audio, not better. The real benefit is that no additional quality is lost in the conversion, and the file is safe for repeated processing without further degradation.
MP4 files typically store audio using AAC, a highly efficient lossy codec that achieves small file sizes by permanently discarding audio data deemed less perceptible. ALAC, by contrast, is lossless — it compresses audio without any data loss, which results in significantly larger audio files. Additionally, the original MP4 file size included both a video stream and an audio stream, whereas the ALAC output contains only audio, but lossless audio is inherently larger than a comparable lossy track.
ALAC has broad but not universal support. It plays natively on all Apple devices and software including iPhones, iPads, Macs, iTunes, and Apple Music. On non-Apple platforms, support varies — VLC, foobar2000, and most modern media players handle ALAC well, but some Android devices and older hardware may not support it without additional apps. If you need lossless audio with wider compatibility, FLAC is a more universally supported alternative, though it requires a different conversion.
FFmpeg generally attempts to copy metadata from the source file, but the extent of preservation depends on what metadata is embedded in the MP4. Standard tags like title, artist, and album are typically carried over because both MP4 and ALAC's M4A container use the same iTunes-style metadata format. However, chapter data embedded in the MP4 is supported by ALAC/M4A containers and may also be preserved, while subtitle tracks and multiple audio tracks are not supported by ALAC and will be dropped.
ALAC does not offer adjustable quality settings the way lossy codecs like AAC or MP3 do — it is always lossless, so there is no quality parameter to tune. The only way the output quality could be improved is by starting with a higher-quality source MP4. You can, however, adjust the sample rate or channel count using flags like -ar (sample rate) and -ac (audio channels) if you need to downsample for specific device compatibility, but doing so would alter the audio data.
The displayed command processes a single file, but you can adapt it for batch processing in a terminal. On macOS or Linux, use a shell loop: `for f in *.mp4; do ffmpeg -i "$f" -vn -c:a alac "${f%.mp4}.m4a"; done`. On Windows Command Prompt, use: `for %f in (*.mp4) do ffmpeg -i "%f" -vn -c:a alac "%~nf.m4a"`. This processes every MP4 in the current directory and outputs a matching ALAC M4A file for each one.
Technical Notes
ALAC (Apple Lossless Audio Codec) stores audio in an MPEG-4 container with the .m4a extension, the same container used by AAC audio from Apple's ecosystem. Because both the source MP4 and the output M4A use MPEG-4 containers, metadata in the iTunes/MP4 atom format transfers cleanly. However, ALAC does not support subtitle tracks or multiple simultaneous audio tracks — if your MP4 contains multiple audio streams (e.g., director's commentary plus main audio), only the first/default stream will be extracted. ALAC supports up to 8 channels of audio and sample rates up to 384 kHz, so high-resolution source audio is preserved without decimation. One important limitation: ALAC cannot be streamed over the web in most browsers, as it lacks native HTML5 audio support, making it primarily suited for local playback and archival use. The lossless nature of ALAC means file sizes are typically 2–4x larger than equivalent AAC files at high bitrates, though significantly smaller than uncompressed PCM WAV or AIFF files of the same audio.