Free online WMA to AT3 converter

What the WMA format is

WMA, or Windows Media Audio, is a Microsoft audio format used for music downloads, media libraries, Windows applications, and older portable devices. Windows Media Player and other Microsoft-based software commonly create .wma files; the extension can contain WMA Standard, WMA Professional, or WMA Lossless audio.

What the AT3 format is

AT3 usually refers to Sony ATRAC3 audio stored in a RIFF/WAVE-style file with the .at3 extension. It was used by Sony hardware and software, including some PSP audio workflows and older Sony music products. ATRAC3 is lossy compression designed for relatively small files, but it is not the same codec as ATRAC3plus and does not have universal playback support.

How to actually convert WMA to AT3

The built-in converter at 101convert.com can convert the file for free without installing software: open the WMA-to-AT3 converter, select the .wma file, start the conversion, and download the generated .at3 file. Check the destination device's required sample rate, channel count, and ATRAC3 bitrate before relying on the output.

For local conversion, FFmpeg can decode most WMA variants and encode ATRAC3 when the installed build includes the atrac3 encoder:

ffmpeg -i input.wma -c:a atrac3 -ar 44100 -ac 2 -b:a 132k -f wav output.at3

The -f wav option writes ATRAC3 audio in a RIFF/WAVE container while retaining the requested .at3 filename. Use ffmpeg -encoders | findstr atrac3 on Windows or ffmpeg -encoders | grep atrac3 on macOS and Linux to verify encoder availability. If the target device specifies another supported bitrate, replace 132k; do not use an arbitrary bitrate.

When FFmpeg produces a file that a Sony application rejects, use Sony software that includes an ATRAC3 export component, such as a compatible version of Sound Forge, and choose File → Save As or File → Export, then select ATRAC3 and the device's required profile. Older Sony plug-ins may not run on current operating systems.

Quality and compatibility limits

WMA-to-AT3 conversion normally decodes one lossy codec and re-encodes the audio with another, so it cannot restore detail already discarded by WMA. Use the highest-quality available WMA source, keep the original for archiving, and avoid repeated conversions.

AT3 compatibility depends on more than the filename: applications may require 44.1 kHz stereo, a particular ATRAC3 bitrate, a RIFF/WAVE container, or a device-specific folder and naming scheme. Test a short converted file on the intended hardware before converting a large library. WMA Lossless still becomes lossy ATRAC3 after conversion.