.aifc File Extension

What kind of file is an .aifc?

An .aifc file is an Audio Interchange File Format Compressed file, usually called AIFF-C. Apple extended the original AIFF container so its common chunk could identify different audio encodings. Despite the name, AIFF-C is not always compressed. The NONE compression code stores ordinary PCM, while other codes cover floating-point PCM, A-law, mu-law, and additional encodings.¹

AIFF-C has no registered IANA MIME type. Software commonly uses audio/x-aiff or audio/aiff.² Identification should check the bytes as well as the suffix:

FORM alone is not sufficient because other IFF-family formats share it. Ordinary AIFF instead has AIFF at offset 8.¹

How do I open an .aifc on my computer?

Adobe Audition opens .aifc on Windows and macOS, including uncompressed AIFF files and most common compressed variants. It documents support for files with up to 32 channels.³ FFmpeg can inspect and decode AIFF-C on Windows, macOS, and Linux.⁴

Compatibility depends on the encoding inside the container. An app that opens uncompressed AIFF may reject an AIFF-C file using an uncommon compression code. Web-browser playback is also inconsistent, so convert a copy to a broadly supported delivery format when sharing online.

Poly support for .aifc

Poly can store, sync, share, version, download, and find .aifc files by name. Poly does not currently infer an audio MIME type from this suffix alone. When an upload source supplies audio/x-aiff, Poly treats the file as audio, extracts available duration and tags, creates audio-similarity segments, and transcribes intelligible speech for full-text search.

Correctly classified files open in Poly's audio player, but playback still depends on the browser decoding the file's particular encoding. The Poly agent can use supported audio and its transcript. Instrumental audio may have little useful transcript text.

History of .aifc

Apple published AIFF version 1.3 in 1989 after adapting Electronic Arts' IFF chunk model for sampled sound.⁵ The AIFF-C specification followed in 1991. It added a compression-type field while preserving the extensible chunk structure, allowing the container to describe more than the original AIFF's uncompressed audio.¹

The final c in .aifc distinguishes the extended form from .aif and .aiff. It indicates the AIFF-C structure, not proof that the sound data is smaller than PCM.

Working with .aifc and alternatives

Convert to PCM or FLAC without resampling or reducing bit depth when preserving decoded quality matters. This cannot recover information already lost by a lossy codec inside the AIFF-C file. Keep the original when its metadata or application-specific chunks matter.