About CAF Files
Apple Core Audio
CAF (Core Audio Format) is Apple audio container supporting any codec.
Family
Audio Files
Extension
.caf
MIME Type
audio/x-caf
Can Use As
HOW CAF
CAME TO BE.
CAF — Core Audio Format — shipped with Mac OS X 10.4 Tiger in April 2005 as Apple’s answer to WAV’s 4 GB file size limit. By the mid-2000s professional audio was bumping into that ceiling: a 24-bit 96 kHz multi-track recording could overflow WAV in under an hour. CAF uses 64-bit chunk sizes, so file size is effectively unlimited.
Inside Apple CAF is used for system sounds, GarageBand projects, Logic Pro session audio, and iOS app sound effects. It supports any codec that Core Audio can decode: PCM, Apple Lossless, AAC, IMA ADPCM, and more. Outside Apple, CAF is rare — most non-Apple audio tools stick with WAV or BWF for interchange. If you get a .caf file, it’s almost certainly from a macOS or iOS development workflow.
CURIOSITIES &
TRIVIA.
CAF uses 64-bit file sizes — you can record continuously at 96 kHz/24-bit for days without hitting a limit.
iOS app developers often ship short sound effects as CAF because Core Audio decodes them with minimal CPU.
Logic Pro stores every track in a project as CAF — switching to WAV forces re-encoding.
CAF supports "annotations" — arbitrary text chunks that can carry song lyrics, timing cues, or session notes.
GarageBand files (.band) internally embed CAF audio for each track.
STRENGTHS &
LIMITATIONS.
Strengths
- Unlimited file size (64-bit offsets).
- Can hold any Core Audio codec (PCM, ALAC, AAC, etc.).
- Native Apple ecosystem support.
- Rich annotation and metadata capabilities.
Limitations
- macOS/iOS-centric — limited non-Apple tool support.
- Not a delivery format — exists for workflow, not consumption.
- Proprietary but documented.
- No broad industry adoption; WAV / BWF dominate interchange.
Typical Sizes & Weights
iOS app sound effect (short)
10-200 KB
1 hour Logic Pro track (24-bit 48 kHz)
~620 MB
Multi-track session (10 hours, 32 tracks)
100+ GB
Technical Specifications
- MIME type
- audio/x-caf
- Extension
- .caf
- Container
- Chunked, 64-bit sizes
- Codecs
- PCM, ALAC, AAC, IMA ADPCM, µ-law, Opus, FLAC
- Max size
- 2^64 bytes (effectively unlimited)
CONVERT FROM
CAF
Common Use Cases
macOS/iOS audio development
Related Formats
Popular comparisons
CAF vs FLAC
Differences, file size, and when to choose each format.
CAF vs AAC
Differences, file size, and when to choose each format.
CAF vs M4A
Differences, file size, and when to choose each format.
CAF vs OGG
Differences, file size, and when to choose each format.
CAF vs OPUS
Differences, file size, and when to choose each format.
CAF vs WMA
Differences, file size, and when to choose each format.
Popular CAF conversions
The most-requested destinations when starting from CAF.
Frequently Asked Questions about CAF
Frequently Asked Questions
CAF (Apple Core Audio) is an audio file format used to store sound recordings — music, voice, podcasts, sound effects. The format defines how the audio samples are compressed (or stored raw), what bitrates are supported, and how metadata such as title, artist, album, and cover art is embedded. It is part of the audio files family.
VLC, foobar2000, and the default media players on Windows and macOS handle CAF natively. On mobile, iOS Music and Android media apps vary in their support — popular formats work everywhere; niche ones may need a dedicated app. If playback fails on a device, converting to MP3 or AAC usually solves it.
Upload the CAF to KaijuConverter and pick MP3, WAV, FLAC, AAC, OGG, or any other target. Our FFmpeg pipeline decodes the audio and re-encodes to the target format at sensible default bitrates (VBR ~190 kbps for music, 96 kbps for speech). Metadata and cover art travel with the audio where both formats support them.
CAF can be lossy or lossless depending on the specific variant. Lossy variants (smaller files) discard some audio detail during compression in ways tuned to be inaudible; lossless variants preserve every sample exactly but produce larger files. For distribution, lossy at high bitrate is standard; for archival, lossless wins.