The Windows Media Audio 10 Professional (WMA 10 Pro) Lossless decoder implements the full WMA 10 Pro decoder and adds the creation of a bit-for-bit duplicate of the original audio file so that no data is lost. Different profiles cover bit streams ranging from 44.1 kHz stereo streams to 192 kHz 7.1 streams. In addition the decoder supports lossy profiles that include everything from full-resolution 24-bit/96 kHz audio in stereo, to 5.1- or 7.1-channel surround sound, to highly efficient mobile capabilities at 24 Kbps to 96 Kbps for stereo, and 128 Kbps to 256 Kbps for 5.1-channel sound.
It's been optimized for maximum exfficiency on Tensilica's HiFi Audio DSP cores. Check it out.