audio rate conversion library libsamplerate (aka Secret Rabbit Code) performs audio rate conversion. This can be used to downsample and upsample audio from 4Hz up to 192kHz. You can also define custom resample rates. An example application would be converting a 44.1kHz sample rate used on CDs to the 48kHZ sample rate used by DAT Devices. libsamplerate provides a number of different interpolation algorithms and is capable of time varying conversions and arbitary up and down sampling. Further information is available at <http://www.mega-nerd.com/SRC/>.