Resampling Improvements

by poljar for PulseAudio

PulseAudio aims to match the sample rates supported by the hardware to the sample rates requsted by the application. This process is called resampling and is quite CPU intensive. PulseAudio resorts mostly to external code to provide resampling: speex, ffmpeg, libsamplerate. Speex seems unmaintained, ffmpeg now provides a library interface (libav) and code duplication is unnecessary (we have a copy of the ffmpeg resampler in our source tree). Lightweight, high-quality and optimized resampling code is desirable.