Audio Format Comparison

CAF vs AIFF: Apple's Core Audio Format vs Industry Standard Uncompressed

CAF (Core Audio Format) is Apple's modern audio container designed to overcome AIFF's 4 GB file size limit and add support for multiple audio streams in a single file. Both are lossless uncompressed formats, but CAF is Apple-only while AIFF has broader (though still limited) cross-platform support.

CAFvsAIFF

Quick Verdict

Use CAF when…

Use CAF for iOS/macOS audio development and when working with audio files larger than 4 GB (hour-long recordings). CAF supports more audio codecs and audio channels than AIFF and is the preferred format for Apple's Core Audio framework.

Use AIFF when…

Use AIFF for cross-application compatibility within audio production — AIFF works in Pro Tools, Logic Pro, Ableton, and most audio editors. AIFF is better understood outside Apple's native APIs.

CAF vs AIFF: Feature Comparison

Feature	CAF	AIFF
Max file size	No limit	4 GB (2 GB on older systems)
Multi-stream support	Yes	No
Codec support	Multiple (PCM, AAC, ALAC, MP3, ima4)	PCM primarily
Cross-platform support	macOS/iOS only	Wider (but still limited)
DAW support	Logic Pro, Garageband native	Universal in professional DAWs
Lossless storage	Yes (PCM or ALAC in CAF)	Yes (PCM)
Streaming suitability	Not practical	Not practical

When CAF wins

✓Max file size: No limit
✓Multi-stream support: Yes
✓Codec support: Multiple (PCM, AAC, ALAC, MP3, ima4)

When AIFF wins

✓Max file size: 4 GB (2 GB on older systems)
✓Multi-stream support: No
✓Codec support: PCM primarily

Frequently asked questions

How do I convert CAF to AIFF?

On Mac with afconvert (built-in): `afconvert -f AIFF -d I16LE input.caf output.aiff`. This converts to 16-bit AIFF. For 24-bit: `-d I24LE`. With FFmpeg: `ffmpeg -i input.caf -c:a pcm_s24be output.aiff` (AIFF uses big-endian PCM). Audacity also opens CAF files and exports to AIFF. The conversion is lossless if the CAF contains PCM audio.

Why does iOS use CAF for long recordings?

CAF files have no size limit — critical for long recordings. AIFF files larger than 4 GB are corrupted on some systems. A 4-hour stereo recording at 44.1 kHz/24-bit is about 5 GB — safely stored in CAF, problematic in AIFF. CAF also stores sample-accurate timestamps and other metadata valuable for multi-take recording sessions in apps like Voice Memos or DAW mobile apps.

Can Pro Tools open CAF files?

Pro Tools does not natively open CAF files. Convert CAF to AIFF or WAV before importing into Pro Tools: use afconvert (Mac command line), Audacity, or the Permute app. Logic Pro opens CAF natively (it's both Mac-native apps). Most professional DAWs prefer AIFF or WAV for uncompressed audio interchange.