The VCKernel.lib library exports a set of functions that provide a convenient interface between a kernel-mode video capture driver and its user-mode counterpart. If you link your kernel-mode driver with VCKernel.lib, your driver can easily respond to I/O request packets (IRPs) sent to it by a user-mode driver that is using VCUser.lib, the companion library for user-mode video capture drivers. (For more information about IRPs, see the Kernel-Mode Drivers Design Guide.)
The VCKernel.lib library provides a dispatch function that recognizes the I/O request codes and control codes that a user-mode driver can place inside the IRPs. The driver provides a set of driver functions used with VCKernel.lib, which the library calls in response to the receipt of the control codes.