Audio Interchange File Format

AIFF is based on the Interchange File Format (IFF), a container structure developed by Electronic Arts. An AIFF file consists of a series of chunks, each with a type ID, size, and data. The essential chunks include the FORM chunk (the overall container), the COMM chunk (describing sample rate, bit depth, and channel count), and the SSND chunk (containing the actual audio samples).¹ The format supports sample rates up to 192 kHz and bit depths up to 32-bit floating point, though 16-bit/44.1 kHz is the most common configuration. Because AIFF stores audio in big-endian byte order, it is natively suited to Motorola 68000-based Macintoshes, but it can be read on little-endian systems with byte swapping.²

Apple introduced AIFF in 1988 as part of the System 7 operating system, aiming to provide a standard format for high-quality audio on Macintosh computers. It was quickly adopted by early digital audio workstations and music software, such as Digidesign's Pro Tools, which used AIFF as a native format for multitrack recording.³ In 1991, Apple released AIFF-C, a variant that supports compressed audio data, including MACE and μ-law codecs, while retaining the same file structure. AIFF's uncompressed nature made it a favorite for professional audio editing and mastering, where bit-perfect preservation is critical. Although WAV (Microsoft's format) became more prevalent on Windows, AIFF remains widely supported on macOS, iOS, and many cross-platform applications.⁴

AIFF and WAV are both uncompressed PCM formats, but they differ in byte order: AIFF uses big-endian, while WAV uses little-endian. This difference can cause compatibility issues when transferring files between systems, though modern software handles both transparently. Unlike compressed formats like MP3 or AAC, AIFF retains all original audio data, making it ideal for archival and professional use, but it results in large file sizes—approximately 10 MB per minute for 16-bit/44.1 kHz stereo audio.⁵ AIFF also supports metadata chunks, such as ID3 tags, allowing for track titles and album information, though this is less standardized than in WAV. For lossless compression, Apple Lossless (ALAC) is often preferred over AIFF for portable devices, but AIFF remains a benchmark for fidelity in studio environments.⁶

Beyond its standard use, AIFF has several niche features. The format supports an ANNO chunk for annotation text, and a MARK chunk for cue points, which are used in editing and looping. AIFF-C can embed compressed audio using codecs like A-law and μ-law, which are common in telephony, making it a bridge between consumer and telecom audio. In the 1990s, AIFF was used in early multimedia CD-ROMs and video game soundtracks, such as those for the 3DO console. The format also influenced the development of the Broadcast Wave Format (BWF), which extends WAV with broadcast metadata, but AIFF's big-endian structure was adopted by the AES31 standard for audio interchange. Additionally, AIFF files can store multiple audio channels, including 5.1 surround, though this is rarely implemented in consumer tools.⁷

PCM

Pulse-code modulation, a method of digitally representing analog signals.

Chunk

A block of data in an IFF-based file, identified by a type ID and size.

Big-endian

Byte order where the most significant byte is stored first.

AIFF-C

A variant of AIFF that supports compressed audio data.

MACE

Macintosh Audio Compression/Expansion, a codec used in AIFF-C.