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Guide

AIFF Format: The Complete Guide to Audio Interchange File Format

PC By Pablo Cirre •

What Is AIFF?

AIFF stands for Audio Interchange File Format, a lossless audio container format developed by Apple and Electronic Arts in 1988. AIFF stores uncompressed PCM (Pulse-Code Modulation) audio data — the same raw digital audio representation used in professional recording studios, CD audio, and broadcast production.

AIFF was designed for the Macintosh and became the native audio format of macOS and professional Apple audio software (Logic Pro, GarageBand, Final Cut Pro). It is the Apple ecosystem's equivalent of WAV (which serves the same role on Windows). Today AIFF remains widely used in professional audio production, music mastering, and archiving workflows that demand lossless quality.

File Structure: Interchange File Format (IFF)

AIFF is built on the IFF (Interchange File Format) chunk structure, originally developed by Electronic Arts and Jerry Morrison for the Amiga computer in 1985. IFF organises data as a hierarchy of typed chunks:

FORM chunk (outer container)
  FORM size          (4 bytes, big-endian)
  AIFF identifier    ("AIFF" — 4 bytes)

  COMM chunk (required)
    numChannels      (2 bytes) — 1=mono, 2=stereo, 6=5.1
    numSampleFrames  (4 bytes) — total number of sample frames
    sampleSize       (2 bytes) — bits per sample (8, 16, 24, 32)
    sampleRate       (10 bytes) — 80-bit extended precision float (unusual!)

  SSND chunk (Sound Sample Data — required)
    offset           (4 bytes) — byte offset into block
    blockSize        (4 bytes) — block alignment size (0 for no alignment)
    soundData        (variable) — raw PCM audio samples

  MARK chunk (optional) — markers (cue points, loop start/end)
  INST chunk (optional) — instrument settings (used in samplers)
  MIDI chunk (optional) — MIDI data
  AESD chunk (optional) — audio recording information
  APPL chunk (optional) — application-specific data
  NAME chunk (optional) — name string
  AUTH chunk (optional) — author string
  (c)  chunk (optional) — copyright string
  ANNO chunk (optional) — annotation strings

Big-endian byte order: AIFF stores all multi-byte integers in big-endian (Motorola) byte order, reflecting its Macintosh/68000 origins. This contrasts with WAV, which uses little-endian (Intel) byte order.

Sample rate storage: The sampleRate field in the COMM chunk is stored as a 10-byte IEEE 754 80-bit extended precision floating-point number. This is unusual — most formats use a simple integer for sample rate. The extended precision accommodates rates like 44,100, 48,000, 88,200, 96,000, 176,400, and 192,000 Hz without loss.

Audio Data: PCM Format

The SSND chunk contains raw PCM audio samples:

  • Bit depth: 8, 16, 24, or 32 bits per sample. 16-bit is CD quality; 24-bit is professional recording quality.
  • Channels: Interleaved — for stereo, the samples alternate: L₁ R₁ L₂ R₂ L₃ R₃ ...
  • Signed integers: Samples are signed two's complement integers (unlike WAV 8-bit which is unsigned).
  • No header within SSND: The block data is raw samples without any internal framing.

File size formula:

File size ≈ (bit_depth / 8) × num_channels × sample_rate × duration_seconds

A 5-minute stereo 24-bit/96kHz AIFF:

= (24/8) × 2 × 96,000 × 300
= 3 × 2 × 96,000 × 300
= 172,800,000 bytes ≈ 165 MB

AIFF vs. AIFF-C (AIFC)

Apple also defined AIFF-C (Audio Interchange File Format Compressed), using the chunk type identifier AIFC instead of AIFF:

FORM chunk
  AIFC identifier    ("AIFC" instead of "AIFF")

  COMM chunk (extended for compression)
    ... same as AIFF COMM ...
    compressionType    (4 bytes) — codec identifier ('NONE', 'sowt', 'fl32', etc.)
    compressionName    (Pascal string) — human-readable codec name

Common AIFC compression types:

  • NONE — uncompressed PCM (same as plain AIFF)
  • sowt — little-endian PCM ("swapped" — same samples as WAV)
  • fl32 — 32-bit IEEE 754 floating-point PCM
  • fl64 — 64-bit IEEE 754 floating-point PCM
  • alaw — G.711 A-law logarithmic compression (telephony)
  • ulaw — G.711 μ-law logarithmic compression (telephony)
  • MACE3 / MACE6 — Macintosh Audio Compression and Expansion (Apple proprietary)

The sowt (little-endian PCM) format is interesting because it is byte-for-byte identical to a WAV file's audio data — only the header structure differs.

AIFF vs. WAV vs. FLAC vs. ALAC

Feature AIFF WAV FLAC ALAC
Compression None None Lossless Lossless
Byte order Big-endian Little-endian N/A N/A
Max bit depth 32-bit 32-bit 32-bit 32-bit
Max sample rate Any (80-bit float) 4 GHz theoretically Any Any
Container IFF chunks RIFF chunks FLAC stream MP4/M4A
Metadata Limited chunks ID3 tags (unofficial), BWF (broadcast) Vorbis Comments iTunes metadata
File size Same as WAV Same as AIFF ~50-60% smaller ~50-60% smaller
Apple native Yes No No Yes
Windows native No Yes No No
Professional use Yes Yes Archiving Apple ecosystem

AIFF vs. WAV: The two formats are functionally equivalent — both store uncompressed PCM. The differences are byte order (big-endian vs. little-endian) and chunk container (IFF vs. RIFF). Any DAW (Digital Audio Workstation) can handle both. The choice typically reflects OS preference: macOS users default to AIFF; Windows users default to WAV.

AIFF vs. FLAC: Both are lossless, but FLAC applies lossless compression reducing files by 40-60%. FLAC is preferred for storage and distribution; AIFF/WAV are preferred in active DAW projects where disk bandwidth matters (compressed audio requires decompression on every read).

Professional Use Cases

Music mastering: Mastered audio is typically delivered as 24-bit/44.1kHz or 24-bit/96kHz AIFF or WAV. Many mastering engineers prefer AIFF on macOS-based workflows.

Sample libraries: Instrument samples in Native Instruments, EastWest, Spitfire Audio, and other professional sample libraries are distributed as 24-bit/96kHz AIFF or WAV.

Logic Pro / GarageBand: Apple's DAWs use AIFF as their native audio format for rendered tracks, bounces, and exported stems.

Broadcast and post-production: AIFF files (or broadcast WAV with BWF metadata) are the standard delivery format for audio in television and film post-production.

iTunes / Apple Music: The iTunes Store historically used AIFF for the highest-quality option before transitioning to Apple Lossless (ALAC).

Limitations

  • No lossless compression: AIFF files are large. A 24-bit/96kHz stereo recording uses 3× more disk space than a 16-bit/44.1kHz WAV of the same duration.
  • Limited metadata: AIFF lacks standardised ID3 or VorbisComment metadata. Some tools add metadata in the APPL chunk, but compatibility is inconsistent.
  • Big-endian only: Original AIFF is big-endian; some older Windows tools may not handle it correctly (though modern tools handle both byte orders).
  • No DRM: AIFF cannot carry DRM information. Protected Apple Music downloads use ALAC with FairPlay DRM, not AIFF.

Converting AIFF

AIFF → MP3: Lossy compression from lossless source. Use iTunes/Music app on macOS, Audacity, ffmpeg. Always convert from the lossless master; never convert MP3 to MP3 through AIFF.

AIFF → FLAC: Lossless-to-lossless transcode. FFmpeg: ffmpeg -i input.aiff output.flac. File size reduces ~50%. No quality loss.

AIFF → WAV: Functionally equivalent; just byte order conversion. FFmpeg: ffmpeg -i input.aiff output.wav. Useful for Windows compatibility.

AIFF → ALAC: Apple's lossless format in M4A container. iTunes/Music app on macOS handles this natively.

WAV/FLAC → AIFF: FFmpeg: ffmpeg -i input.wav output.aiff or ffmpeg -i input.flac output.aiff.

Summary

AIFF is a mature, professional-grade lossless audio format that occupies the same niche on macOS as WAV does on Windows. Its uncompressed PCM storage guarantees perfect audio fidelity with no generation loss through repeated open/save cycles — essential for professional music production and mastering. Its IFF chunk architecture is well-defined, its 80-bit sample rate field handles any professional sample rate without approximation, and its Apple ecosystem integration makes it the natural choice for Logic Pro users. For archiving, FLAC is more storage-efficient; for cross-platform compatibility, WAV is more universally supported; for Apple-centric workflows, AIFF remains the standard.

Related conversions

Audio format pairs that come up most often:

Related conversions

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Frequently Asked Questions

AIFF and WAV are functionally equivalent formats — both store uncompressed PCM audio at the same quality. The technical differences are byte order (AIFF uses big-endian, WAV uses little-endian) and container structure (AIFF uses IFF chunks, WAV uses RIFF chunks). AIFF is the macOS native format (used by Logic Pro); WAV is the Windows native format. Any modern audio application handles both transparently.

AIFF e WAV are functionally equivalent formatoos — both store não comprimido PCM audio at the same quality. The technical differences are byte order (AIFF uses big-endian, WAV uses little-endian) e container structure (AIFF uses IFF chunks, WAV uses RIFF chunks). AIFF is the macOS native formato (used by Logic Pro); WAV is the Windows native formato. Any moderno audio aplicativo handles both transparentely.

AIFF und WAV are functionally equivalent Formate — both store uncompressed PCM audio at the same quality. The technical differences are byte order (AIFF uses big-endian, WAV uses little-endian) und Container structure (AIFF uses IFF chunks, WAV uses RIFF chunks). AIFF is the macOS native Format (used by Logic Pro); WAV is the Windows native Format. Any modern audio Anwendung handles both transparently.

AIFF y WAV are functionally equivalent formatoos — both store uncompressed PCM audio at the same quality. The technical differences are byte order (AIFF uses big-endian, WAV uses little-endian) y contenedor structure (AIFF uses IFF chunks, WAV uses RIFF chunks). AIFF is the macOS native formato (used by Logic Pro); WAV is the Windows native formato. Any moderno audio aplicación handles both transparentely.

For long-term archiving choose <strong>FLAC</strong> (lossless, ~50% the size of WAV). For everyday listening on phones and streaming use <strong>MP3 320 kbps</strong> or <strong>Opus 192 kbps</strong> (transparent quality, no audible difference at normal volumes). Avoid converting lossy → lossy → lossy: every step compounds artifacts.

Yes. Standard AIFF stores uncompressed PCM audio with no quality loss. AIFF-C (AIFC) can store compressed audio (using codecs like MACE or μ-law), but these are rare in modern workflows. For lossless compression with smaller file sizes, FLAC or Apple Lossless (ALAC) are alternatives that compress AIFF-equivalent quality into 40-60% smaller files.

Yes. padrão AIFF stores não comprimido PCM audio com no quality loss. AIFF-C (AIFC) can store comprimido audio (using codecs like MACE ou μ-law), mas these are rare in moderno workflows. para sem perdas compressão com smaller tamanho do arquivos, FLAC ou Apple sem perdas (ALAC) are alternatives that compress AIFF-equivalent quality em 40-60% smaller files.

Yes. Standard AIFF stores uncompressed PCM audio mit no quality loss. AIFF-C (AIFC) can store komprimiert audio (using Codecs like MACE oder μ-law), aber these are rare in modern workflows. für verlustfrei Komprimierung mit smaller Dateigrößes, FLAC oder Apple verlustfrei (ALAC) are alternatives that compress AIFF-equivalent quality in 40-60% smaller files.

Yes. estándar AIFF stores uncompressed PCM audio con no quality loss. AIFF-C (AIFC) can store comprimido audio (using codecs like MACE o μ-law), pero these are rare in moderno workflows. para sin pérdidas compresión con smaller tamaño de archivos, FLAC o Apple sin pérdidas (ALAC) are alternatives that compress AIFF-equivalent quality en 40-60% smaller files.

Spoken-word podcasts: 44.1 kHz mono, 64–96 kbps Opus or 96 kbps MP3. Music podcasts: 44.1 kHz stereo, 128–192 kbps. Going above wastes bandwidth — speech has limited frequency content above 7 kHz, and listeners on data plans appreciate the smaller file. Apple Podcasts and Spotify both accept up to 48 kHz / 320 kbps.

For pure archiving (maximum storage efficiency, preservation), FLAC is better: it is lossless, compresses to 40-60% smaller files, has excellent metadata support (Vorbis Comments), and is universally supported. For active DAW projects where you repeatedly open and save files (especially on macOS/Logic Pro), AIFF is practical because no decompression is needed on every read. For long-term archives, FLAC is the community standard.

For pure archiving (maximum storage efficiency, preservation), FLAC is better: it is sem perdas, compresses to 40-60% smaller files, has excellent metadata support (Vorbis Comments), e is universally suportado. para active DAW projects where you repeatedly abrir e salvar arquivos (especially on macOS/Logic Pro), AIFF is practical because no decompression is needed on every read. para long-term archives, FLAC is the community padrão.

For pure archiving (maximum storage efficiency, preservation), FLAC is better: it is verlustfrei, compresses to 40-60% smaller files, has excellent metadata support (Vorbis Comments), und is universellly unterstützt. für active DAW projects where you repeatedly öffnen und speichern Dateien (especially on macOS/Logic Pro), AIFF is practical because no decompression is needed on every read. für long-term archives, FLAC is the community Standard.

For pure archiving (maximum storage efficiency, preservation), FLAC is better: it is sin pérdidas, compresses to 40-60% smaller files, has excellent metadata support (Vorbis Comments), y is universally soportado. para active DAW projects where you repeatedly abrir y guardar archivos (especially on macOS/Logic Pro), AIFF is practical because no decompression is needed on every read. para long-term archives, FLAC is the community estándar.

Lossy → lossy compounds quantization noise. Each encode discards the same kind of perceptual information again, multiplying artifacts. Always re-encode from a lossless master if you have one (WAV, FLAC, or the original recording). If only an MP3 is available, keep the bitrate at or above the source — never go up to "improve quality".

For professional recording and production: 24-bit/96kHz (or 24-bit/48kHz). For CD mastering delivery: 24-bit/44.1kHz. For archiving vinyl or tape: 24-bit/96kHz. The 32-bit/192kHz setting in some DAWs is mainly for internal processing overhead, not distribution. Avoid 8-bit AIFF (very low quality) and 16-bit for new recordings (limited dynamic range); use 16-bit only when converting final masters for CD or streaming delivery.

For profissional recording e production: 24-bit/96kHz (or 24-bit/48kHz). para CD mastering delivery: 24-bit/44.1kHz. para archiving vinyl ou tape: 24-bit/96kHz. The 32-bit/192kHz setting in some DAWs is mainly para internal processing overhead, not distribution. Avoid 8-bit AIFF (very baixa qualidade) e 16-bit para new recordings (limited dynamic range); usar 16-bit only when convertendo final masters para CD ou streaming delivery.

For professionell recording und production: 24-bit/96kHz (or 24-bit/48kHz). für CD mastering delivery: 24-bit/44.1kHz. für archiving vinyl oder tape: 24-bit/96kHz. The 32-bit/192kHz setting in some DAWs is mainly für internal processing overhead, not distribution. Avoid 8-bit AIFF (very niedrig quality) und 16-bit für new recordings (limited dynamic range); verwenden 16-bit only when umwandelnd final masters für CD oder streaming delivery.

For profesional recording y production: 24-bit/96kHz (or 24-bit/48kHz). para CD mastering delivery: 24-bit/44.1kHz. para archiving vinyl o tape: 24-bit/96kHz. The 32-bit/192kHz setting in some DAWs is mainly para internal processing overhead, not distribution. Avoid 8-bit AIFF (very baja quality) y 16-bit para new recordings (limited dynamic range); usar 16-bit only when convirtiendo final masters para CD o streaming delivery.

Most modern tools (FFmpeg with <code>-map_metadata 0</code>, foobar2000, dBpoweramp) preserve ID3 tags and embedded cover art. Some quick-and-dirty converters strip them silently. KaijuConverter preserves tags in its <a href="/convert/flac-to-mp3">audio conversions</a>; if metadata is critical to you, verify the output with <code>ffprobe</code> before deleting the original.