Tremor
Tremor is a fixed-point (integerized) low-level (Ogg) Vorbis decoding library (BSD-license) designed for embedded microprocessors that can't perform floating point calculations (which includes many popular Digital Audio Players lines such as the IRiver H-Series, Rio Karma, and the Rockbox firmware.) There is talk of implementing a fixed-point encoder version of Tremor, so that encoding can be done on an integerized DSP platform feasibly (see xiph.org mailing list). Tremor has helped Vorbis gain considerable hardware support amongst manufacturers in the last few years. (Korean companies being a notable example).