Free online OGG to AA3 converter

Some Sony audio players and legacy SonicStage/OpenMG libraries expect ATRAC3 audio in an .aa3 file rather than Ogg audio. Converting is also useful when an older Sony device cannot import OGG directly.

What the OGG format is

OGG is a multimedia container; in audio files, it most commonly contains Vorbis audio, although Ogg Opus and Ogg FLAC files also exist. Audacity, FFmpeg, games, media applications, and recording tools commonly create OGG files, and media players often use them for compressed music, sound effects, and voice recordings.

The .ogg extension does not by itself identify the codec. Check the file with MediaInfo or FFmpeg before converting if the source may contain Opus or another codec.

What the AA3 format is

AA3 is a Sony ATRAC audio file, generally associated with ATRAC3 compression and the SonicStage/OpenMG software ecosystem. It was used for smaller music files on Sony devices and in Sony-managed music libraries.

ATRAC3 files can be substantially smaller than uncompressed WAV files while retaining the format expected by compatible Sony hardware and software. AA3 is a legacy format, so support outside Sony applications and older players is limited; some programs identify related files as .oma instead.

How to actually convert OGG to AA3

1. Open the 101convert.com audio converter, which can convert the file online for free without installing software.
2. Add the source .ogg file and select AA3 as the output format.
3. Start the conversion and download the resulting .aa3 file when processing finishes.
4. Test the file in the intended Sony application or device. If it rejects the file, check whether that product requires .oma, a particular ATRAC3 bitrate, or OpenMG-protected content.

For a local workflow, FFmpeg can encode ATRAC3 when the installed build includes the ATRAC3 encoder and Sony OpenMG Audio muxer:

ffmpeg -i input.ogg -c:a atrac3 -b:a 132k -ar 44100 -ac 2 -f oma output.aa3

The -f oma option forces the Sony OpenMG Audio container; the .aa3 filename does not guarantee that the file has the required container. If the target software expects the conventional extension, use output.oma instead, or rename the completed file only after confirming that the device accepts AA3-named files.

Another desktop route is to decode the OGG to WAV with FFmpeg, then import the WAV through SonicStage → Import and select an ATRAC3 output setting if the installed SonicStage version supports it. SonicStage is discontinued, and its import, encoding, and transfer behavior varies by version.

Quality and compatibility limitations

OGG-to-AA3 is normally a lossy-to-lossy conversion. The ATRAC3 encoder cannot restore detail removed when the OGG file was created, so retain the original recording when possible and avoid repeated conversions.

Use a bitrate supported by the destination device; 132k is a common ATRAC3 setting, but older Sony products may accept only specific bitrates, sample rates, channel layouts, or transfer modes. OpenMG DRM and device authorization can also prevent a technically valid ATRAC3 file from playing, and ordinary converters cannot create the original protected license data.