Ever so quietly, a new open source ATRAC3 decoder implementation has been slipped into FFmpeg. This decoder handles atrc data inside of RealMedia files or in WAV files.
Thanks to Benjamin Larsson and Maxim Poliakovski for their diligent work on this, as well as the guru for his tireless reviewing efforts and uncompromising code quality standards.
Is there some kind of page or wiki entry or something that says “these are all the different ATRAC related codecs, formats and containers and these are the ones that currently have open source implementations”?
Not yet, but I wager there will soon be one.
Search for Atrac on the multimedia wiki and on wikipedia. Might answer some of your questions.