The SysAudio driver represents audio filter graphs as virtual audio devices and registers each virtual audio device as an instance of a KSCATEGORY_AUDIO_DEVICE device interface. The SysAudio system driver (Sysaudio.sys) builds the filter graphs that render and capture audio content. The kernel-mode WDMAud driver is a kernel streaming (KS) filter and a client of the SysAudio system driver. WDMAud performs I/O for the following APIs: waveIn, waveOut, midiIn, midiOut, mixer, and aux (described in the Microsoft Windows SDK documentation). The pair of WDMAud drivers translate between user-mode Microsoft Windows multimedia system calls and kernel-streaming I/O requests. The kernel-mode WDMAud system driver (Wdmaud.sys) is paired with the user-mode WDMAud system driver (Wdmaud.drv). USB Audio Class System Driver (Usbaudio.sys)ĪVCAudio Class System Driver WDMAud System Driver Port Class Adapter Driver and PortCls System Driver The kernel-mode Microsoft Windows Driver Model (WDM) audio components are:
