Winamp MPC Plugin is needed to play MPC, MPP or MP+ files with Winamp (2 or 5). It supports ReplayGain, Crossfade Plugins and ignores ID3v2 tags (which are definitely not supported by MPC!)
Related Terms
What is MPC?
Musepack is an audio compression format with high quality of compressing.
The ATSurround Processor is a DSP plugin for the foobar2000 and Winamp audio player. It is able to extract surround information inherently present in many music and audio sources to enhance the listening experience.