GPAC - Gulli's Perceptual Audio Codec. Here's the report in Postscript format. The audio samples are located here .
Source code is here , mainly in the src , include and project directories.
The meat of the coder and decoder is in the files gpacenc.cpp, gpacdec.cpp, anasynth.cpp and bitcode.cpp . You can also fetch the whole thing in one .tar.gz package .