Free online AT3 to AU converter

Source format: AT3

AT3 usually refers to ATRAC3 audio, a compressed audio format developed by Sony. It is commonly found in PlayStation Portable content, some Sony media files, and older portable-device workflows. AT3 is used when smaller file size matters more than lossless quality, and it is often encountered in game audio, handheld console assets, and archived Sony audio collections.

Target format: AU

AU is a simple audio container format originally associated with Unix systems. It can store uncompressed PCM audio and, in some cases, compressed data depending on the encoder and player support. AU is valued for its wide compatibility in Unix-like environments, straightforward structure, and usefulness in software testing, legacy systems, and basic audio interchange.

How to perform the conversion

The most reliable way to convert AT3 to AU is to first decode the AT3 audio to PCM and then save it as AU. A practical desktop tool for this is FFmpeg, which supports many audio formats and is well suited for batch conversion.

1. Install FFmpeg on your computer.
2. Open a terminal or command prompt.
3. Run a command such as ffmpeg -i input.at3 output.au.
4. If the source file contains multiple streams or unusual metadata, inspect it first with ffmpeg -i input.at3.
5. If needed, specify the audio codec explicitly, for example ffmpeg -i input.at3 -c:a pcm_s16be output.au for standard PCM output in AU.

If you prefer a simpler workflow, you can also convert the file on 101convert.com for free without installing any software.

Notes on quality and compatibility

AT3 is lossy, so the conversion to AU cannot restore audio detail that was already discarded during ATRAC3 compression. The resulting AU file may be much larger than the original AT3, especially if it is saved as uncompressed PCM. This conversion is best when you need a more broadly readable file for Unix tools, archiving in a simple container, or further processing.

Compatibility depends on the AU variant used. Some players expect PCM AU specifically, while others support only limited AU encodings. If playback fails, try exporting to standard PCM audio in AU or choose a more universally supported format such as WAV for intermediate use.