What Is AIFF? Apple's Lossless Audio Format

The Short Answer

AIFF — Audio Interchange File Format — is Apple's uncompressed PCM audio container, originally published in 1988. It predates Microsoft's WAV format by three years, stores audio identical in fidelity to WAV, and remains the default export format for GarageBand and (until recently) Logic Pro. If you have ever exported a song from an Apple music tool and ended up with a 30+ MB '.aiff' or '.aif' file, that is uncompressed AIFF: every sample preserved, no compression, no perceptual coding, no quality loss of any kind.

The catch is the same one as WAV: huge files, weak compatibility outside Apple's ecosystem, and obsolete metadata compared to FLAC or ALAC.

A Brief History

AIFF was developed by Apple in 1988, primarily for use on the Macintosh II and the early Audio CD authoring workflows of the late 1980s. It is a direct adaptation of the Interchange File Format (IFF) that Electronic Arts created for the Commodore Amiga in 1985 — IFF was already a chunk-based generic container used for graphics ('ILBM'), animation ('ANIM'), text, and music modules.

Apple kept IFF's basic structure: a top-level 'FORM' chunk identifying the document type ('AIFF'), followed by a sequence of subchunks each with a 4-character ID and a 32-bit length. The Common chunk ('COMM') describes the audio (channels, sample frames, bit depth, sample rate as an 80-bit IEEE 754 extended-precision float — yes, really), and the Sound Data chunk ('SSND') holds the PCM samples.

Crucially, AIFF uses big-endian byte order — the most-significant byte first — because the Motorola 68000 CPU in early Macs was big-endian. Microsoft's WAV, derived from the same IFF idea three years later, switched to little-endian to match the Intel 8086 family Windows ran on. This single byte-order difference is the entire technical distinction between the two formats. The audio data is otherwise identical PCM.

AIFF preceded WAV by three years and is therefore arguably the more historically significant of the two — it is the first widely deployed digital audio file format on personal computers. It just lost the platform popularity contest to WAV when Windows took over.

How AIFF Stores Audio

The structure is straightforward:

• FORM chunk — the outer wrapper. Bytes 0–3 = 'FORM', 4–7 = total file size minus 8, 8–11 = 'AIFF' (or 'AIFC' for compressed variants).
• COMM chunk — number of channels, number of sample frames, bit depth, and sample rate (stored as an 80-bit IEEE 754 extended-precision float, which is unusual but lets AIFF represent any sample rate exactly).
• SSND chunk — the audio payload. Optional offset and block size headers, then interleaved PCM samples in big-endian byte order.
• Optional chunks — 'NAME' (track name), 'AUTH' (author), 'COPY' (copyright), '(c) ' (copyright notice), 'ANNO' (annotation), 'COMT' (comments with timestamps), 'INST' (instrument data — base note, detune, loop points), 'MARK' (named position markers), 'MIDI' (raw MIDI data), 'AESD' (AES recording metadata).

The interesting things in that list are 'INST' and 'MARK'. They are why early Mac samplers (Akai S-series via SoundDesigner II and friends) and DJ software liked AIFF: a single file can carry sample loop points, root note, and named cue markers without external sidecar files. WAV bolted on equivalents later ('smpl' chunk for loops, 'cue ' for markers), but AIFF had them from day one.

AIFF-C: The Compressed Variant

In 1991 Apple extended AIFF with AIFF-C (also written AIFC), adding a 'COMM' field that names a compression algorithm — essentially a four-character codec ID like 'NONE' (uncompressed), 'sowt' (uncompressed little-endian, ironically), 'fl32' (32-bit float), 'ima4' (IMA ADPCM 4:1 compression), 'MAC3' / 'MAC6' (Apple's proprietary MACE codecs), 'GSM ', 'ulaw', 'alaw', and various others.

In practice, AIFF-C with anything other than 'NONE', 'sowt', or 'fl32' is rare in modern files. The compressed AIFF-C variants were largely supplanted by ALAC, FLAC, and AAC. When a tool today writes an AIFF file, it is almost always uncompressed PCM — the AIFF-C extension exists but is mostly historical.

File Size

AIFF size math is identical to WAV's because the audio payload is identical PCM:

bytes ≈ sample_rate × bit_depth/8 × channels × seconds + ~50 byte header

Plugging in:

• CD quality (44.1 kHz, 16-bit, stereo): about 10.1 MB per minute.
• 48 kHz / 24-bit stereo: about 17.3 MB per minute.
• 96 kHz / 24-bit stereo: about 34.6 MB per minute.

A typical pop album at CD quality is about 480 MB as AIFF. The same album as 320 kbps MP3 is roughly 100 MB. As FLAC, about 250 MB.

AIFF inherits the same 4 GB classic-container limit as WAV (the chunk size fields are 32-bit). Long recordings need newer extensions or just a different container. Most modern DAWs that need to write more than 4 GB switch to RF64/BW64 (a WAV variant) rather than extending AIFF.

Bit Depth and Sample Rate Support

AIFF supports the same range of PCM configurations as WAV:

• Bit depths: 1 to 32 bits per sample integer; 32-bit and 64-bit float via AIFF-C ('fl32', 'fl64').
• Sample rates: anything representable as an 80-bit float, which covers every rate that has ever shipped on any audio device.
• Channels: mono, stereo, and multichannel up to 65,535 channels in principle, with no formally specified surround channel ordering — different tools have used different orderings, which has caused some interoperability headaches in surround production.

For typical use you will encounter 16-bit/44.1 kHz (CD), 16-bit/48 kHz (broadcast), 24-bit/48 kHz (Logic Pro internal), and 24-bit/96 kHz (Logic Pro high-resolution). These all work identically to their WAV equivalents. See the WAV explainer and the PCM audio explainer for the underlying digital audio fundamentals.

Where AIFF Is Used

AIFF's natural habitat is the Apple ecosystem:

• GarageBand — exports audio to AIFF by default. The 'Share → Export Song to Disk' dialog defaults to "AIFF" with bit-depth options.
• Logic Pro — historically used AIFF as the internal recording format. Modern Logic (10.4+) defaults to CAF or WAV internally but still imports/exports AIFF without trouble.
• macOS — Finder, QuickTime, and the Music app all play AIFF natively. Spotlight indexes AIFF metadata.
• iTunes / Music app — can import from CD as AIFF or AIFF-C, though Apple Lossless (ALAC) is the default lossless choice.
• Older sample libraries — Akai S-series patches, EXS24 instruments, and many vintage sample CDs ship AIFF.
• DJ software — Serato, Rekordbox, and Traktor all read AIFF, and some DJs prefer it for its cue point handling.

Outside Apple, AIFF is a second-class citizen. Most Windows DAWs read it (Reaper, Cubase, Studio One, FL Studio) but write WAV by default. Linux audio tools read it. Hardware players are spottier — many automotive head units and Bluetooth speakers either reject AIFF outright or play only the PCM data while ignoring metadata.

AIFF vs WAV

For most practical purposes, AIFF and WAV are interchangeable:

• Audio quality — identical. Both store the same PCM samples in the same bit depths.
• File size — identical for the same audio, within a few bytes of header difference.
• Byte order — AIFF big-endian, WAV little-endian. Modern CPUs handle both with no measurable performance difference.
• Metadata — AIFF wins slightly on out-of-the-box capability (NAME/AUTH/COPY/ANNO/COMT, plus INST and MARK for samples). WAV's LIST/INFO chunks are weaker, though WAV's BWF extension adds broadcast-grade timecode metadata that AIFF lacks.
• Cross-platform support — WAV is broader. Pretty much every audio tool ever made reads WAV. AIFF support outside Apple is universal in DAWs but uneven in consumer hardware.
• Broadcast workflows — WAV (specifically BWF) is the deliverable. AIFF is not used for broadcast.

The practical rule: use AIFF if you live entirely inside Apple software and plan to stay there. Use WAV if your collaborators or downstream tools are mixed-platform. Converting between the two is lossless and instant — the AIFF to WAV converter just changes the byte order and rewrites chunk headers.

When to Convert AIFF

AIFF files are big and not universally supported, so the common conversion targets are:

• AIFF → MP3 — for sharing, emailing, posting to the web. Use the AIFF to MP3 converter at 192 kbps or higher; the quality loss is inaudible to most listeners. Detail: AIFF to MP3 guide.
• AIFF → WAV — for sending to Windows collaborators or DAWs with better WAV interop. Lossless, instant. Detail: AIFF to WAV guide.
• AIFF → FLAC or ALAC — for archival. Halves the file size with zero quality loss; FLAC has broader cross-platform support, ALAC integrates better with Apple's Music app.

For one-off jobs the AIFF converter handles all common targets in your browser. The PCM audio explainer covers what is going on under the hood for any uncompressed format.

When AIFF Is Worth Keeping

Three real reasons to stick with AIFF rather than converting away:

1. You are inside an active Logic Pro / GarageBand session and the AIFF files are the project's recorded takes. 2. You have a sample library with embedded INST/MARK metadata that downstream samplers depend on. Converting to WAV preserves the audio but may strip those chunks. 3. You are working with a DJ playout system that has been configured against AIFF cue points.

Outside those three cases there is no audio-quality reason to prefer AIFF over WAV, FLAC, or ALAC. The choice becomes about which container your tools speak best.

AIFF is the older, slightly more elegant cousin of WAV — same audio fidelity, slightly better native metadata, much smaller install base. It will keep existing as long as Logic and GarageBand keep writing it, which is to say indefinitely. But for new work, FLAC for archives and WAV for cross-platform sessions are usually the better defaults.