M4A
→
AU

Convert M4A to AU Online

Convert M4A to AU online. Start with free daily conversions, no install, no watermarks, and visible job status.

M4A to AU Converter

Upload your M4A file to convert it to AU format

Loading converter...

How to Convert M4A to AU

Follow these simple steps

1

Step 1: Upload Your File

Upload your M4A file by dragging and dropping or clicking to browse

2

Step 2: Select Output Format

AU is automatically selected as the output format

3

Step 3: Start Conversion

Click the Convert button to start the conversion

4

Step 4: Download Result

Download your converted AU file when ready

Convert M4A to AU - Complete Guide

Converting M4A to AU stays in the audio file family but changes the traits that decide size, quality, transparency, editability, or device support. M4A is an audio format commonly used by Apple devices, music libraries, podcasts, and mobile recordings. AU is a audio format. Sun audio. Below is what actually changes in a M4A→AU conversion, what is preserved, and when AU is the better choice than keeping M4A.

What changes when you convert M4A to AU

  • The audio is re-encoded into the AU format. Because re-encoding is not free, start from the highest-quality source you have and keep quality settings high.
  • Expect a larger output file: AU stores M4A content with less aggressive compression.

About the M4A format

M4A is Apple's audio format, typically containing AAC or ALAC encoded audio. It is commonly found in iTunes purchases and Apple Music downloads.

  • Full name: MPEG-4 Audio
  • Developer: Apple
  • Compression: AAC or ALAC
  • Opens with: Apple devices, iTunes, most players

Where M4A is strong: high-quality AAC audio in a tidy container; standard for Apple Music and voice memos; supports metadata and cover art.

Typical M4A uses: Apple music libraries, podcasts and voice memos, mobile recordings.

About the AU format

AU is a audio format. Sun audio.

  • Compression: mixed
  • Opens with: VLC, Audacity, FFmpeg

Where AU is strong: simple legacy format from Sun/NeXT systems; stores uncompressed PCM or companded mu-law/A-law audio; easy to read and parse.

Typical AU uses: legacy Unix and Java system sounds, older audio archives.

What AU keeps

  • AU adds: simple legacy format from Sun/NeXT systems.

Things to watch out for

  • AU is less universally supported than M4A — make sure your target player or platform accepts AU before converting.
  • One AU limitation to keep in mind: dated format rarely used today.

When to convert M4A to AU

  • Convert M4A to AU for legacy Unix and Java system sounds.
  • Convert M4A to AU for older audio archives.
  • Pick AU when you need stores uncompressed PCM or companded mu-law/A-law audio.

M4A vs AU — format comparison

A quick side-by-side of the structural differences between M4A and AU, so you can confirm this is the right conversion for your file:

AttributeM4AAU
TypeAudio fileAudio file
CompressionLossyFlexible (lossy or lossless)
Web-friendlyYesNo
Typical file sizeSmallMedium
Best forApple music librarieslegacy Unix and Java system sounds

Privacy & Security

Files are handled for the conversion you request. Uploads and downloads use HTTPS/TLS, and temporary files are cleared after the processing and deletion window.

Add this M4A to AU converter to your site

Put a working M4A to AU converter on your own blog or website — free to embed. Both options below include a small link back to FreeFastConverter.

Embeddable widget (iframe)

Paste this where you want a live converter. Visitors can convert M4A to AU without leaving your page:

Widget Embed Codeiframe

Simple link badge

Prefer a lightweight button instead? Copy this HTML badge:

HTML Badge CodeLink

Need the opposite conversion?

Convert AU to M4A

Other M4A Conversions

More formats you can convert M4A to

Convert M4A to MP3Convert M4A to WAVConvert M4A to AACConvert M4A to OGGConvert M4A to FLACConvert M4A to WMAConvert M4A to AIFFConvert M4A to OPUSConvert M4A to AC3Convert M4A to AMRConvert M4A to CAFConvert M4A to MKAConvert M4A to WVConvert M4A to SPXConvert M4A to OGAConvert M4A to DTSConvert M4A to MP2
View all M4A conversions →

Convert to AU

Other formats you can convert to AU

Convert MP3 to AUConvert WAV to AUConvert AAC to AUConvert OGG to AUConvert FLAC to AUConvert WMA to AUConvert AIFF to AUConvert OPUS to AUConvert AC3 to AUConvert AMR to AUConvert CAF to AUConvert MKA to AUConvert WV to AUConvert SPX to AUConvert OGA to AUConvert DTS to AUConvert MP2 to AU
View all AU conversions →

Popular Related Conversions

Convert M4A to MP3

M4A to AU FAQ

Converting M4A to AU preserves the content faithfully; output also depends on the source file and any settings you choose.
Upload your M4A file, confirm AU as the output format, and click Convert. Job status is shown while the file is processed, then you can download the AU result.
Yes. You can start with free daily conversions, with no signup required for your first jobs and no watermarks on the output. Accounts and paid plans are available for higher-volume work.
No. The M4A to AU conversion runs in your browser on any device — Windows, Mac, Linux, iOS, or Android — with uploads and downloads over HTTPS.
M4A is Apple's audio container format, commonly used for iTunes music. It typically contains AAC-encoded audio.
Upload your M4A file and select MP3 as output. The conversion preserves audio quality.
Yes, M4A can contain ALAC (Apple Lossless) audio, which is lossless quality.
Processing time depends on file size, format, and queue load. The page shows job status while conversion runs.
Yes. You can add multiple M4A files to a batch and process them together within the current file-size and credit limits.

Related tools

Convert M4A to AU Now

Start with 10 free daily conversions. No signup required for your first file jobs.

Convert Now