This is another part of the SHOUTcast. DSP originally is a plugin for Winamp and is used to 'broadcast' signal to SHOUTcast DNAS server. This allows us to transmit sound from both Winamp and from external sources such as DJ mixer.
This plugin allows you to configure several outputs for transmission, thus allowing broadcasting to multiple radios, or channels at the same time, eg in different qualities. DSP gives us the opportunity to enter various details such as the name of the program and the DJ and the currently playing track.
For more on how to install, configure, and use the plug-in, see How to broadcast in SHOUTcast.

You can download newest version of DSP plugin from SHOUTcast official page