Windows Vista allows third-party audio hardware manufacturers to include custom host-based digital signal processing effects as part of their audio driver's value-added features. These effects are packaged as user-mode System Effect Audio Processing Objects (sAPOs).
There are three insertion points for sAPOs: pre-mix render, post-mix render, and capture. Each logical device’s audio engine supports one instance of a pre-mix render sAPO per stream (render LFX) and one post-mix render sAPO (GFX). The audio engine also supports one instance of a capture sAPO (capture LFX) that is inserted in each capture stream.
This white paper provides guidelines for device driver developers who want to create and install custom sAPOs.
This information applies to the Windows Vista operating system.
Future versions of this preview information will be provided in the Microsoft Windows Driver Kit (WDK).