How to convert .mp3 audio to .at3 format.
Converting MP3 Audio Files directly to ATRAC3 Audio Files (.mp3 to .at3 conversion) is certainly possible and quite straightforward.
Several modern multimedia editing programs and conversion tools, such as Sound Forge Pro or VEGAS Pro, allow users to easily convert .mp3 to .at3.
A dedicated audio production program
A digital audio editing software
Video, Audio & Streaming for creators.