USB diver

I am a new user of QNX 6.3.0 and to develop a personal software I need to
get video data from a USB webcam. I have no idea on how to realize it when I
see all the qnx functions to do it.
So, is there someone to help me to use the useful functions to do it : I
want to put video data in a buffer every 33 ms (30 p/sec).

Thank you for your pecious help!!!