MMegaConvert

Convert M4A to AU

Free online M4A to AU converter. No signup required.

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Max file size: 100 MB

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How to Convert M4A to AU

Follow these simple steps to convert your file in seconds.

  1. 1

    Upload your .m4a file

    Drag and drop your .m4a file into the upload area, or click "Browse" to select it from your device. Your file is uploaded securely and processed on our servers.

  2. 2

    Click "Convert to AU"

    Once your file is uploaded, press the convert button to start the M4A to AU conversion process.

  3. 3

    Wait for the conversion to complete

    The conversion usually takes just a few seconds. You can see the progress in real time while your file is being processed.

  4. 4

    Download your converted .au file

    When the conversion is finished, click the download button to save your new .au file. The file is ready to use immediately.

Understanding M4A and AU Formats

Learn about the source and target file formats to understand what happens during conversion.

Source Format

M4A Audio

audio/mp4

M4A is an audio-only MPEG-4 container file that typically contains either AAC or Apple Lossless (ALAC) encoded audio. It was popularized by Apple as the default format for music purchased from the iTunes Store and ripped from CDs in iTunes. M4A files support rich metadata including album art, lyrics, and chapter markers.

Advantages

  • Better audio quality than MP3 when using AAC encoding
  • Supports both lossy (AAC) and lossless (ALAC) audio codecs
  • Rich metadata support including album art, lyrics, and chapters

Limitations

  • Slightly less universal compatibility than MP3 on older devices
  • Can be confusing due to containing different codecs (AAC vs ALAC)
  • Some older car stereos and portable players lack M4A support

Common Uses

  • iTunes and Apple Music audio library storage
  • Audiobooks and podcasts with chapter markers
  • High-quality music distribution on Apple platforms

Target Format

Sun AU Audio

audio/basic

AU is an audio file format introduced by Sun Microsystems and commonly associated with Unix and NeXT systems. It supports various encodings including uncompressed PCM, mu-law, and A-law compression, with a simple header structure. AU was one of the earliest audio formats supported on the web and remains used in Unix-based audio programming.

Advantages

  • Simple, well-documented format with a minimal header
  • Native support in Unix, Solaris, and Java audio APIs
  • Supports multiple encoding types including mu-law for telephony

Limitations

  • Largely obsolete for general-purpose audio use
  • Limited metadata support and no modern compression options
  • Poor support in consumer audio software and devices

Common Uses

  • Unix and Solaris system audio and sound effects
  • Java application audio playback (javax.sound)
  • Legacy telephony and voice processing systems

Frequently Asked Questions

Common questions about converting M4A to AU.

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