To read about AVStream, see the AVStream Overview.ĭVD Decoder Minidrivers are clients of stream.sys. To learn about the stream.sys driver, refer to Streaming Minidrivers. This section contains legacy documentation on the following topics relevant to the original (pre-XP) ks.sys class driver:įor more information about portcls.sys, see Audio Drivers. In Windows XP SP2 and later, Microsoft provides the USB Video Class driver. In Windows XP and later, ks.sys is referred to as AVStream.
These class drivers are implemented as export drivers (kernel-mode DLLs) in the system files portcls.sys, stream.sys, and ks.sys.
The vendor writes a minidriver that runs under one of these three class driver models. Microsoft provides three multimedia class driver models: port class, stream class, and AVStream. Kernel streaming (KS) refers to the Microsoft-provided services that support kernel-mode processing of streamed data.
