Format guide
What is ALAC?
Apple Lossless Audio Codec is Apple’s lossless audio codec, often stored in M4A/CAF containers, created by Apple (2004). ALAC keeps bit-perfect audio like FLAC but fits Apple ecosystems. Prefer FLAC for open cross-platform archives; ALAC for iTunes/Apple Music lossless libraries.
ALAC format specifications
- Full name
- Apple Lossless Audio Codec
- Kind
- lossless audio
- File extension
- .m4a (ALAC), .caf
- MIME type
- audio/mp4
- Developer / standard
- Apple · 2004
- Compression
- Lossless ALAC
- Quality model
- Lossless / not lossy
- Container
- No / single bitstream typical
- Common codecs
- —
- Technical sources
- —
- Transparency
- Not supported
- Animation
- No (still / non-animated typical use)
- Typical size
- Smaller than WAV; comparable ballpark to FLAC
- Browser support
- Limited compared with MP3/AAC — convert for web delivery
- Compatibility
- Excellent on Apple; improving elsewhere; FLAC still broader in enthusiast Linux/Android niches
ALAC compression & quality
Lossless compression similar in goal to FLAC — smaller than WAV, no quality loss vs PCM source. Device/support story differs from FLAC.
Quality: Lossless — bit-perfect vs source PCM
Typical size: Smaller than WAV; comparable ballpark to FLAC
Transparency & animation
Not applicable.
Not applicable.
ALAC metadata
MP4/iTunes-style tags; artwork common in Apple libraries.
Best use cases for ALAC
- Apple lossless libraries
- iTunes/Music app archives
- Lossless inside M4A
When to avoid ALAC
- Open-source-only pipelines
- Non-Apple devices that prefer FLAC
- Tiny podcast downloads (use AAC/MP3)
Advantages
- Lossless
- Apple-native
- Smaller than WAV
- Familiar M4A packaging
Disadvantages
- Less universal than FLAC in FOSS stacks
- Easy to confuse with lossy AAC .m4a
- Not ideal as a web download default
Compatibility
Excellent on Apple; improving elsewhere; FLAC still broader in enthusiast Linux/Android niches
Browsers: Limited compared with MP3/AAC — convert for web delivery
Software support
- Apple Music
- XLD
- ffmpeg-based tools
- Many DAWs via decode
Device support
- iPhone, Mac, Apple ecosystem; selective Android support
How to open ALAC
Play in Apple Music or convert/transcode with tools that decode ALAC. Confirm the M4A is ALAC not AAC.
How to convert ALAC
Convert ALAC to FLAC for open archives or to AAC/MP3 for delivery. Keep ALAC/WAV as masters when needed.
Popular ALAC conversions
ALAC comparison guides
Compare ALAC with related formats to pick the right container for quality, size, and compatibility.
Best format guides featuring ALAC
Decision pages that cite ALAC — the next hop after a vs comparison.
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ALAC tools
Tools extend the format graph beyond one-off conversion — compression, metadata, and utilities for real workflows.
ALAC FAQ
Is every M4A file ALAC?
No. Most M4A files are lossy AAC. ALAC is a lossless codec that can also use .m4a.
Are my ALAC files uploaded on Format Convertly?
No. ALAC conversion runs in your browser. Files are not sent to Format Convertly servers for processing.