aiff

AIFF, or Audio Interchange File Format, is a standard for storing digital audio data. It was developed by Apple in 1988 as part of the Interchange File Format family and is designed for high-fidelity audio storage. AIFF files are typically used on Macintosh systems but are supported across many platforms. The format emphasizes uncompressed PCM data and uses big-endian byte order, making it a common choice for professional audio workflows alongside WAV.

AIFF files have a chunked structure that organizes data and metadata. The FORM chunk identifies the file as AIFF, and the file contains mandatory chunks such as COMM (the common chunk) and SSND (the sound data chunk). The COMM chunk stores essential metadata, including the number of channels, the total number of sample frames, the sample size in bits, and the sample rate. Notably, the sample rate is stored as an 80-bit floating-point value. The SSND chunk holds the actual audio samples, along with an offset and a block size that control where the audio data begins and how it is aligned.

AIFF-C, also known as AIFC, is a compressed variant of AIFF that enables use of various codecs within the same container. It maintains the same overall structure but adds a compression type, indicated by a four-character code, and accompanying parameters. This allows AIFF-C files to contain either lossy or lossless compressed audio, while preserving compatibility with AIFF tooling and metadata conventions.

Usage and compatibility: AIFF is widely supported in professional audio software and on macOS, valued for its high-quality, uncompressed PCM. It is less prevalent in consumer web contexts where WAV or compressed formats are more common. AIFF files typically use the .aiff or .aif extensions; AIFF-C adds flexibility for exchange where compression is required.