MMegaConvert

Convert AU to AMR

Free online AU to AMR converter. No signup required.

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Max file size: 100 MB

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How to Convert AU to AMR

Follow these simple steps to convert your file in seconds.

  1. 1

    Upload your .au file

    Drag and drop your .au 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 AMR"

    Once your file is uploaded, press the convert button to start the AU to AMR 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 .amr file

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

Understanding AU and AMR Formats

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

Source 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

Target Format

AMR Audio

audio/amr

AMR (Adaptive Multi-Rate) is a compressed audio format optimized specifically for speech encoding, widely used in mobile telecommunications. It employs adaptive bitrate encoding that adjusts between 4.75 and 12.2 kbps based on network conditions, prioritizing speech intelligibility over music quality. AMR is the standard speech codec for GSM and UMTS mobile networks worldwide.

Advantages

  • Extremely small file sizes optimized for voice content
  • Adaptive bitrate adjusts to network conditions in real-time
  • Standard codec in GSM/3G mobile networks worldwide

Limitations

  • Very poor quality for music or non-speech audio
  • Limited to narrowband (8 kHz) or wideband (16 kHz) sampling
  • Not suitable for high-fidelity audio or media production

Common Uses

  • Mobile phone voice recording and voice memos
  • Cellular voice call encoding in GSM/3G networks
  • MMS voice message attachments

Frequently Asked Questions

Common questions about converting AU to AMR.

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