I am capturing the image using OpenCV in C++
firstFrame = cvQueryFrame(capture);
it is easy to set the width and height properties by
cvSetCaptureProperty( capture, CV_CAP_PROP_FRAME_WIDTH, WIDTH );
cvSetCaptureProperty( capture, CV_CAP_PROP_FRAME_HEIGHT, HEIGHT );
I wonder if there is a way to specify the color depth as well without further processing the frame?