Free online AT3 to MP3 converter

Sony hardware and older media software may require ATRAC3 files, while phones, editors, car stereos, and general-purpose players commonly support MP3 instead. Converting the audio makes it easier to play, edit, share, and archive without the original Sony software.

What the AT3 format is

.at3 is commonly used for Sony ATRAC3 compressed audio. ATRAC3 appeared in SonicStage and OpenMG workflows and on devices such as PlayStation Portable systems, Network Walkman players, and some Sony recording products. An AT3 file can contain music, voice recordings, or other audio encoded with the ATRAC3 codec.

Related Sony audio files may use extensions such as .oma or .aa3. Some Sony files are encrypted or protected by OpenMG DRM; changing the filename extension cannot remove that protection, and a converter cannot process audio without the required authorization.

What the MP3 format is

MP3 is a widely supported lossy audio format that works in phones, web browsers, media players, car stereos, operating systems, and most audio editors. It generally produces much smaller files than uncompressed PCM audio.

ATRAC3 and MP3 both use lossy compression. Converting an AT3 file to MP3 decodes the ATRAC3 audio and encodes it again, so information already discarded by ATRAC3 cannot be restored and a small additional quality loss is possible.

How to convert an AT3 file to MP3

Using 101convert.com: Open the built-in converter, upload the .at3 file, choose MP3 as the output format, start the conversion, and download the resulting .mp3 file. This option requires no installation. Avoid uploading confidential recordings or files subject to distribution restrictions.

Using FFmpeg: A current FFmpeg build can decode supported ATRAC3 streams and encode MP3 through the LAME encoder.

1. Install FFmpeg with the ATRAC3 decoder and libmp3lame encoder enabled.
2. Open a terminal in the folder containing the source file.
3. Run ffmpeg -i input.at3 -map 0:a:0 -c:a libmp3lame -q:a 2 output.mp3.
4. Play the output and verify its duration, channels, and audible quality before deleting the source.

The -q:a 2 option requests high-quality variable-bitrate MP3 encoding, commonly producing approximately 190–250 kbps depending on the audio. Use -b:a 192k instead when a fixed bitrate is required. For multiple files, run the command separately or use a shell script that preserves each source filename.

Quality and compatibility limitations

Conversion works only when the file contains decodable ATRAC3 audio. If FFmpeg or the converter reports an unknown format, invalid data, a missing codec, or a protection error, the file may be an encrypted Sony container rather than a directly convertible ATRAC3 stream. SonicStage or the device that created the file may be required to play or export protected content; SonicStage cannot bypass DRM authorization.

MP3 bitrate cannot improve the quality of the ATRAC3 source. Choose a bitrate at least appropriate for the source quality to avoid unnecessary additional loss, retain the original AT3 files as masters, and avoid repeated lossy conversions. Metadata, album art, timestamps, and device-specific information may not transfer, so check tags after conversion.