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AU to AU Converter

Convert AU to AU online for free. Fast, secure, and high-quality conversion with no sign-up or software required.

Free to useNo file stored beyond 1 hourEncrypted over TLS 1.2/1.3No watermarks

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How it works

Three steps to your converted file

Everything happens in your browser tab - upload, pick a format, download. The heavy lifting runs on our servers.

01

Upload your file

Drag and drop, click to browse, or paste a URL. Batches take up to 20 files at once - 230+ input formats across video, audio, image, document, and archive types.

02

Choose an output format

Pick from over a hundred output formats. Filter by category or search by name - every option is open to everyone, no account needed.

03

Convert & download

Hit Convert and grab your download link moments later. Originals are erased when the job completes; results are cleared within about an hour.

What is an AU file?

The AU file format is a simple container format introduced by Sun Microsystems and NeXT for UNIX-based systems. It typically contains μ-law (mu-law) logarithmic encoded audio data (G.711 standard) stored in a big-endian byte order, identified by the hexadecimal magic number 0x2e736e64 ('.snd'). The file structure consists of a minimal 24-byte header specifying data offset, sample rate, and encoding type, followed by an optional annotation block and the contiguous audio data, making it a standard for early Web audio (Java applets) and SPARCstation workstations.

How to open an AU file

Modern operating systems often lack direct associations for AU files due to their obsolescence. While some Linux distributions and macOS (via Core Audio) may support basic playback, Windows requires third-party software. The VLC media player is the primary recommendation for opening AU files across all platforms; alternatively, Audacity can be used to import the raw data and convert it to modern PCM formats like WAV.

AU Technical Info

Full Name
Sun Microsystems Audio
Developed By
Sun Microsystems / NeXT
Initial Release
1988
MIME Type
audio/basic

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Why RunConvert

The fastest way to convert any file

Purpose-built for speed, privacy, and breadth of format support.

Convert AU to AU in seconds

Every AU to AU conversion runs on our servers, so your device stays fast and the output quality stays intact.

Fast, cloud-powered

No queue, no waiting. Files are processed on high-performance servers and returned in seconds, even for large files.

Secure & private

Encrypted in transit and never shared with anyone. Uploads are erased the moment your job completes, and results shortly after.

Free - no account needed

Convert without creating an account - no credit card, no trial clock. Sign in only if you want history and higher daily limits.

Developer API

Convert AU to AU via API

Automate AU to AU conversions in three steps: create a job, upload your file, then poll for the result.

# 1. Create job
curl -X POST https://api.runconvert.com/v3/jobs \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "tag": "au-to-au",
    "tasks": {
      "upload-file": {
        "operation": "import/upload"
      },
      "convert": {
        "operation": "convert",
        "input": "upload-file",
        "output_format": "au"
      },
      "export-result": {
        "operation": "export/url",
        "input": "convert"
      }
    }
  }'

# 2. Upload your file (use upload_url from the response)
curl -X PUT "$UPLOAD_URL" --upload-file input.au

# 3. Poll for result
curl https://api.runconvert.com/v3/jobs/$JOB_ID?include=tasks \
  -H "Authorization: Bearer YOUR_API_KEY"

Replace YOUR_API_KEY with your RunConvert API key. Get your free API key at runconvert.com/api.