AIFF vs ALAC: Which Format Should You Choose?

AIFF and ALAC are both lossless audio formats from the Apple ecosystem, so neither discards audio information. The practical difference is how the audio is stored. AIFF usually holds uncompressed PCM audio. ALAC applies lossless compression that is reversed on playback. Which one suits you depends on whether you mainly record and edit audio or mainly store and play it.

Define the alternatives

AIFF (Audio Interchange File Format) is a container Apple introduced in the late 1980s. In everyday use it stores uncompressed PCM audio, similar to WAV, and the files typically use the .aif or .aiff extension. A variant called AIFF-C can hold compressed audio, but most AIFF files you encounter are uncompressed.

ALAC (Apple Lossless Audio Codec) is a codec Apple introduced in 2004 and later released as open source. ALAC audio is usually stored in an MPEG-4 container with the .m4a extension, the same extension used for lossy AAC files. You can't tell from the extension alone whether an .m4a file is lossless, so check the codec field in your player or file inspector.

This comparison applies to music libraries, recorded voice or instrument tracks, audio exported from video projects, and archived recordings. It does not cover lossy formats such as MP3 or AAC, except where they affect conversion decisions.

Compare meaningful differences

Audio quality

Both formats are lossless. When an ALAC file is decoded, the output is bit-identical to the PCM audio that was encoded. An AIFF file and an ALAC file made from the same source therefore play back the same audio data. Any audible difference between them points to something else in the chain, such as different source files, resampling, volume normalization or the playback device.

File size

AIFF size depends only on sample rate, bit depth, channel count and duration, so it is predictable. ALAC files are smaller, but the saving depends on the material. Dense, noisy recordings compress less than quiet or simple ones. To estimate the saving for your own library, convert a representative sample and compare the folder sizes. Don't rely on a fixed percentage.

Compatibility

AIFF is widely accepted by audio editors, digital audio workstations and video editing software on both macOS and Windows, because uncompressed PCM is simple to read. ALAC is well supported across Apple devices and Apple's own media apps, and many third-party players handle it too. Support is less consistent in professional editing tools, some hardware players, car stereos and older software. Version matters: an app or firmware release may add or drop support, so check current documentation for the specific device or program you rely on.

Metadata and artwork

ALAC files in an MPEG-4 container use the same tagging system as other .m4a files, so titles, album details and cover art are generally handled consistently by library apps. AIFF can carry metadata, often through embedded ID3 tags, but different apps read and write those tags differently. If tags matter, test a few files in every app that will touch them.

Privacy and file handling

Neither format is inherently more private. What matters is the metadata your software writes. A file can contain names, comments, encoder information, dates or artwork that you did not intend to share. Before you send recordings to someone else, open the file's tag or info view and confirm what is actually stored. Don't assume that converting or exporting removes existing tags.

Processing load

ALAC must be decoded during playback and encoded on export, while uncompressed AIFF needs no decoding. On current computers and phones this is rarely a practical concern for listening. In large editing sessions some workflows still prefer uncompressed files, and some editors convert compressed sources to an internal format on import. Whether this affects you depends on your software and hardware, and only testing on your own setup will show it.

Practical trade-offs

The published specifications tell you what each format can store. They don't tell you how smoothly a given app, device or project will handle it. Separate those two questions when you decide.

• Recording and editing: AIFF is the safer working format, because editors and DAWs handle uncompressed PCM reliably and there is no decode step.
• Music library on Apple devices: ALAC saves storage and keeps tags and artwork organized, with no loss of audio data.
• Archiving master recordings: either works for lossless preservation. AIFF favors broad readability by editing tools, while ALAC favors smaller storage. Keep a checksum or second copy whatever format you pick.
• Sharing with collaborators: AIFF or WAV is less likely to cause import problems in someone else's software. Ask what they use before sending ALAC.
• Playback on non-Apple hardware: confirm ALAC support in the device's current specifications before converting a whole library.

Conversion between AIFF and ALAC is lossless in both directions, as long as you keep the same sample rate and bit depth. Converting from a lossy source such as MP3 or AAC into either format does not restore lost detail. It only makes the file larger.

Choose for the use case

• Choose AIFF if you edit audio, exchange files with editors or video software, or need the widest support among production tools.
• Choose ALAC if you mainly listen within the Apple ecosystem, want smaller lossless files and value consistent tagging.
• Use both if it fits your workflow: keep AIFF working files during a project, then convert finished tracks to ALAC for your listening library.
• Choose neither as a fix for low quality: if the source was lossy or poorly recorded, changing the format won't improve it.

Before converting a large collection, test a handful of files in every app and device you depend on. Confirm that they import, play and show correct tags, then convert the rest and keep your originals until you have verified the results.