AIFF: Audio Interchange File Format

If you have ever heard a file with the .aiff extension, then most likely you have encountered something valuable - a studio recording, an archive or just audio in the highest possible quality. AIFF (Audio Interchange File Format) is one of the oldest digital audio formats, created by Apple back in 1988. It still remains the standard in the professional recording industry - and for good reason.

But behind this simplicity are hidden interesting technical details, little-known bugs and even forgotten functions that only narrow specialists know about. In this article, we will analyze what AIFF really is, why it is still relevant, and what surprises you can encounter when working with this format.

What is AIFF?

AIFF is a digital audio storage container developed by Apple based on the more general RIFF (Resource Interchange File Format) format, which is also used in WAV. AIFF was conceived as a universal and clean format for storing uncompressed PCM audio - that is, lossless audio.

The format became a standard for the Macintosh and remained the main way to store audio in professional Apple applications such as Logic Pro, Sound Designer and even iTunes, where you could export music to AIFF without losing quality.

AIFF does not use compression, so preserving 100% of the original quality comes at a huge size. For example, one minute of stereo audio at 44.1 kHz/16-bit takes up about 10 MB.

With metadata, everything is pretty good. Covers, lyrics, timestamps and even text comments inside the file are supported.

How is AIFF different from WAV?

AIFF and WAV are two of the most popular formats for storing uncompressed audio. Both store data in PCM format, and both provide the same audio quality. However, there are a few important differences:

AIFF is native to macOS, WAV is native to Windows.
AIFF uses big-endian byte order, while WAV uses little-endian byte order.
AIFF can contain extended chunks for storing metadata, such as INST, NAME, AUTH, ANNO, COMM, and even iXML — detailed data about the recording time, studio, and equipment.

WAV, on the other hand, has a strict file size limit of 2 GB due to the use of 32-bit headers. AIFF also suffers from this, but there is a format called AIFF-C (AIFC) that allows data compression and bypasses some of the limitations.

AIFF-C (AIFC): rarely supported, but may surprise

Most users think that AIFF is always uncompressed PCM. In fact, there is an extended version of the format — AIFF-C or AIFC, which supports compression while preserving quality. It is not lossy, like MP3, but simply more efficient data storage. AIFF-C can use different codecs, for example:

G.711 μ-law and A-law — often used in telecommunications.
MACE 3:1 and 6:1 — Apple codecs, which were used in old versions of QuickTime and voicemail systems.
IMA4 ADPCM — a fairly common codec that can be found in old games and audio storage systems.

However, most modern media players do not support AIFC, especially if it uses an unknown codec. Sometimes the file simply does not open, or plays with distortion. This is a real surprise if you work with archives or old Logic Pro projects.

AIFF and rare bugs: what can go wrong

AIFF is a simple format, but it has its own oddities. Here's what you might encounter if you work with AIFF professionally:

Confusion with file extensions

If a format has several versions, then confusion is simply inevitable. Usually the extension consists of three letters, so the compressed AIFF-C also has the extension .aif. As you may have guessed, most programs will consider the file damaged, although it can be decoded. Such files can be found in old sound libraries that used non-standard conversion tools. Many media players do not recognize this and simply do not play the file, giving an error.

File Size Limits

Since the chunk size field of the chunk header is a 32-bit signed integer, and each AIFF can only have one chunk of audio data, the maximum file size is limited to 2 GB. This was OK in the 90s, but is a serious limitation today.

If you plan to make long audio recordings, then on the MacOS platform it is advisable to use the CAF format. For Windows, there are alternatives in the form of RF64 and W64.

Endianess and compatibility

When creating the AIFF format, Apple used Motorola 6800 processors with big-endian byte order, and the audio format inherited these parameters. Most modern processors (including Intel and Apple Silicon) work in little-endian. This means that when working with AIFF on Windows or in some programs, you may need to re-convert the file to avoid distortions.

Apple Silicon (M1/M2) users have complained on forums that some older AIFF files do not play in QuickTime or even Logic Pro. The cause turned out to be an error reading chunks in a 32-bit environment, which appeared due to differences in endianness handling.

AIFF in old Logic Pro projects

You can find stories on audio engineer forums where AIFF files created in Logic Pro played incorrectly in Pro Tools or even Audacity until they were re-converted to WAV. It turned out that Apple used its own internal AIFF format, which contained specific chunks that weren't supported by other editors.

AIFF with an empty NAME chunk

Sometimes AIFF files contain a NAME chunk, but no data. This can cause some DAW programs (like Cubase) to refuse to open it, giving an error. The problem can be solved by deleting the chunk in a hex editor.

AIFF and a metadata bug in Final Cut Pro

On professional film sound editing forums, people reported that Final Cut Pro X incorrectly handles AIFF files with an iXML chunk if they contain unsupported tags. This can cause project failures and even metadata resets.

Little-known features of AIFF

Despite their archaism, RIFF-based formats can contain various data in chunks, which is rarely found in other containers. For example, markers and comments, which completely replace modern CUE files. But this is not all.

AIFF can contain metadata about tempo and pitch

AIFF supports special chunks, such as INST, where you can store information about the instrument's pitch, range, tuning frequency, and even tempo. This is especially important when working with samples and virtual instruments, where it is important to know exactly how the sample should sound.

This data is often ignored when converting to other formats, which can lead to problems when using samples in a DAW.

AIFF in Film and TV: A Format That Doesn't Lose Data

In film production and broadcasting, AIFF remains popular because it can contain an iXML chunk that stores technical information: file name, date, time, timestamps, and even GPS coordinates. This is critical for synchronization and archiving.

AIFF can be multi-channel

AIFF officially supports up to 32 channels. This makes it convenient for working with surround systems, such as 5.1 or 7.1. However, as with AIFC, not all programs handle such files correctly.

Summary

Although the format is over 35 years old, it remains important in many scenarios. AIFF is not just "WAV, but from Apple". It is a flexible, powerful and precise format that remains important in professional environments. It can contain a lot of hidden data, handle multichannel audio, store precise metadata and even include compression.

But be prepared for surprises: not all programs handle AIFF correctly, especially if you encounter AIFC, rare codecs or non-standard chunks.

If you work with archives, record music in the studio, or just like precision, AIFF is your choice. But don't forget to check what's inside, because AIFF is not always pure PCM.