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What is CAF?

Core Audio Format (CAF) is Apple's audio container designed to overcome the file size and sample rate limitations of AIFF and WAV.

What is AU?

Sun AU is the native audio format for Sun Microsystems workstations, using simple mu-law encoding or uncompressed PCM.

When Should You Use CAF vs AU?

Use CAF When...

Reach for CAF when your priority is apple audio production, professional editing — its uncompromising quality ensures every detail is preserved.

Use AU When...

If legacy unix audio, sun workstation sound is your end goal, AU is the smart pick. Its exacting standards ensure your output matches your input at every stage.

CAF vs AU: Key Differences

  • •The core technical difference: CAF relies on lossless compression whereas AU uses lossless compression.
  • •Both formats share lossless compression, so quality behavior is similar across the two — file size differences come from algorithm efficiency rather than compression philosophy.
  • •How transparency is handled: AU supports transparency, so alpha information is preserved during conversion.
  • •Storage footprint: Flexible, supports very large files for CAF vs Small to medium, similar to WAV for AU.
  • •Primary audience: CAF is built for apple audio production, professional editing scenarios, while AU focuses on legacy unix audio, sun workstation sound — pick the format that matches your output requirement.

Advantages of CAF

  • ✓At its core, CAF relies on lossless encoding — a design choice that makes it perfect for Apple audio production, professional editing.
  • ✓You won't run into compatibility issues with CAF — it's a universal standard across platforms.
  • ✓File size management with CAF: larger files guaranteed to match the original exactly.
  • ✓Every major application in the Apple audio production, professional editing space supports CAF natively.

Advantages of AU

  • ✓The lossless nature of AU means file sizes stay reasonable while handling Legacy Unix audio, Sun workstation sound efficiently.
  • ✓From mobile devices to enterprise servers, AU is recognized and supported everywhere.
  • ✓The trade-off for AU's perfection is larger files — but for archival work, it is worth every megabyte.
  • ✓AU is a first-class citizen in all major software ecosystems, from creative suites to development environments.

Common Use Cases for CAF to AU Conversion

  • Professional broadcasting
  • Video game audio assets
  • Film soundtracks
  • Radio commercials
  • Guided meditation recordings
  • Audiovisual installation

Industry Applications

Audio ArchivingGame AudioFilm Post-productionAudiobook PublishingMusic StreamingLive Sound

Best Practices for CAF to AU Conversion

  • →Converting CAF to AU: AU preserves full audio fidelity — ideal for archiving master recordings
  • →Normalize audio levels before conversion for consistent playback volume
  • →AU excels in professional audio workflows
  • →Always keep a backup of your original files before converting
  • →Choose the appropriate quality settings for your specific use case

Related Article

Video Compression Guide: Reduce File Size Without Losing Quality

Learn more about CAF and AU formats in our detailed guide.

Troubleshooting CAF to AU Conversion

  • !Clicks or pops in the converted AU → sample rate conversion can introduce artifacts; use a clean multiple of the source rate
  • !AU file has silence at the beginning or end → trim the source CAF file before converting to avoid unnecessary padding
  • !Stereo image collapsed after converting CAF to AU → verify that the converter preserves channel mapping for multichannel audio
  • !The converted AU clips or distorts at peaks → reduce the gain or apply a limiter before conversion to prevent hard clipping

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Convert CAF to AU Online - Free & Fast

Convert CAF files to AU online for free. High-quality conversion with no registration required.

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About CAF and AU

CAF

CAF (CAF audio) - Core Audio Format, Apple's professional audio format. Best for apple audio production, professional editing.

AU

AU (AU audio) - Sun AU, legacy Unix audio format for Sun workstations. Ideal for legacy unix audio, sun workstation sound.

Format Comparison

CompressionLossless → Lossless
TransparencySupported
Use CaseConvert from apple audio production, professional editing to legacy unix audio, sun workstation sound
File Size~Small to medium, similar to WAV after conversion

FAQs

Is converting CAF to AU free?

Yes, GoConvertFile offers free conversion of CAF to AU for files up to 100MB. No registration required.

How long does it take to convert CAF to AU?

Most CAF to AU conversions complete within seconds for standard-sized files. Larger files may take longer depending on the conversion complexity.

What is AU best used for?

AU is ideal for legacy unix audio, sun workstation sound. Sun AU, legacy Unix audio format for Sun workstations

What file size should I expect after converting CAF to AU?

File size after CAF to AU conversion depends on the content complexity and quality settings. Both formats use similar compression approaches so sizes are comparable.

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