ALAC file format: what it is and how to use it

ALAC is Apple's lossless audio codec inside .m4a: bit-perfect compression for the Apple ecosystem, open-sourced in 2011. Learn when to use it and what to choose instead.

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What is a ALAC file?

An ALAC file holds audio compressed with Apple Lossless Audio Codec, introduced for iTunes in 2004 and open-sourced by Apple in 2011. It typically rides inside an .m4a container. Decoding restores the source PCM bit-for-bit while cutting size to roughly 50–70%. It is, in effect, Apple's answer to FLAC, optimized for light decoding on mobile chips.

When should you use ALAC?

  • Lossless music inside Apple devices: iTunes, Music.app, iPhone and iPod read it natively.
  • CD rips and libraries you edit later: bit-perfect means re-encoding never compiles errors.
  • Hi-res playback on Apple hardware: supports high sample rates and bit depths.

When is another format a better fit?

Outside Apple, FLAC has broader software and hardware support at similar ratios. For pure capture and editing, WAV stays simpler. For listening copies on the move, a good AAC encode is a fraction of the size. Keep ALAC for the library, not the commute.

The short version: ALAC is the Apple-ecosystem lossless, equivalent in spirit to FLAC and best when your world is iPhones and iTunes.

How to open a ALAC file

On Windows

Double-click the file, or open it with Foobar2000.

On macOS

iTunes / Apple Music opens ALAC files on macOS.

Convert instead

Turn ALAC files into another format, right in the browser.

Also opens in

  • iTunes / Apple Music
  • VLC
  • Foobar2000

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ALAC technical details

Full name
Apple Lossless Audio Codec
Extensions
.m4a .alac
MIME type
audio/mp4, audio/x-alac
Magic bytes
… 66 74 79 70 (M4A/MP4 container)
Compression
Lossless
Developer
Apple
Specification
macosforge.github.io

ALAC questions, answered

How do I open an .alac/.m4a file?

iTunes, Music.app, QuickTime, VLC, foobar2000 and most players open it; the codec is open since 2011. dexrr plays and converts it directly in your browser.

Can I convert ALAC files online?

Yes, dexrr converts m4a/alac locally in your browser: ALAC to FLAC for cross-platform lossless, ALAC to WAV for editing or ALAC to MP3 for sharing.

Is ALAC better than FLAC?

They are near-identical in ratio and both lossless, so choose by ecosystem: ALAC for Apple, FLAC for everything else. Neither is 'better sounding'; both restore bit-perfect PCM.

Does converting ALAC to MP3 lose quality?

Yes, MP3 is lossy and that step is irreversible. The ALAC master remains intact if you keep it; convert a copy, never the library original.

Is the ALAC format outdated?

No, it is the standard lossless codec of Apple Music's lossless tier and open-sourced, so support keeps widening.