Hello,
for a DirectShow description look here:
http://en.wikipedia.org/wiki/DirectShowIn short form, DirectShow is a part of DirectX an API ( application programming interface ) from Microsoft.
With this API you can handle (program) video/audio devices.
But the prerequisite to do this is, that the driver of the device is DirectShow compatible.
Nowadays nearly all new drivers are compatible, because each manufacturer wants, that his devices could be used in all applications.
How do you know, that your camera driver is not DirectShow compatible?
There are also open source drivers available from the net, which could work!