What is ALAC?
Complete guide to the ALAC file format
What is it?
ALAC (Apple Lossless Audio Codec) is a lossless audio compression format developed by Apple and released in 2004. Like FLAC, ALAC compresses audio data without any loss of quality - the decoded audio is bit-for-bit identical to the original source. Apple originally kept ALAC proprietary, but open-sourced it in 2011 under the Apache License. ALAC files are stored in the M4A container (the same container used by AAC), using the .m4a file extension.
Apple uses ALAC as the format for lossless streaming on Apple Music, which launched lossless support in 2021. ALAC files are natively supported on all Apple devices including iPhone, iPad, Mac, and Apple TV without any additional software or codec installation. The compression ratio is typically around 40 to 50% reduction compared to uncompressed PCM audio (similar to FLAC), while preserving every sample of the original recording perfectly.
Technical Specifications
Pros & Cons
Advantages
Lossless compression means the decoded audio is identical to the original - no quality loss ever.
Plays natively on all Apple devices and software without any codec installation needed.
The format Apple uses to deliver lossless streaming, supporting up to 24-bit/192 kHz audio.
The codec is open source and freely usable since 2011, despite its Apple origins.
Disadvantages
Lossless files are 2 to 3 times larger than equivalent AAC files - high quality comes at a storage cost.
While open source, ALAC is less widely supported in non-Apple software and hardware players compared to FLAC.
FLAC and ALAC are both lossless and produce identical audio quality; FLAC has broader support outside the Apple ecosystem.
Significantly larger than MP3 or AAC files, requiring more storage and download bandwidth.
When to Use It
Here are the most common situations where ALAC is the right choice:
Apple Music Library
Use ALAC when building a lossless music library intended for Apple devices and software.
iTunes and Music App
ALAC is the recommended lossless format for importing CDs into the Apple Music app on Mac.
Audio Archiving on Apple
Archive ripped CDs and high-resolution audio downloads in ALAC for permanent lossless storage.
High-Resolution Audio
ALAC supports up to 24-bit/384 kHz, making it appropriate for high-resolution audiophile recordings.
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Is ALAC the same quality as FLAC?
Yes. Both are lossless audio codecs - the decoded audio from ALAC and FLAC is bit-for-bit identical to the source. The choice between them is purely about software ecosystem compatibility.
Why does ALAC use .m4a extension instead of .alac?
ALAC is stored inside the MPEG-4 container format (M4A), which is the same container used for AAC audio. The .m4a extension is shared between ALAC and AAC files; you need to check the encoding to know which codec is inside.
Does Apple Music use ALAC for lossless?
Yes. Apple Music's Lossless Audio tier (launched in 2021) streams in ALAC format at up to 24-bit/48 kHz, and Hi-Res Lossless at up to 24-bit/192 kHz.
Can I play ALAC on Android?
Android does not support ALAC natively, but many third-party players like VLC, Poweramp, and USB Audio Player Pro can play ALAC files. Alternatively, convert ALAC to FLAC for universal Android support.
Which is better: ALAC or FLAC?
For Apple-only use, ALAC is more convenient. For cross-platform use, FLAC has broader hardware and software support. Audio quality is identical between the two.