I found this Sony ATRAC3 Audio Codec and if some one can implement it on the JPCSP.
http://www.free-codecs.com/download/sony..._codec.htm
http://www.softpedia.com/progDownload/So...13798.html
http://www.free-codecs.com/download/sony..._codec.htm
http://www.softpedia.com/progDownload/So...13798.html