Cutted Image from OpenCV VideoCapture with changed resolution

Question

when changing the resolution of my input image from webcam its getting cutted and replaced in a strange way. I have two logitech pro 9000 - one is called quickcam the other one not. The Quickcam is working perfectly when changing resolution. The other one doesn't:

original without changed values:

with changed resolution:

This is the code for changing:

cv::Size imageSize(1200,800);
cv::VideoCapture cap1(0);
cap1.set(CV_CAP_PROP_FRAME_WIDTH,imageSize.width);
cap1.set(CV_CAP_PROP_FRAME_HEIGHT,imageSize.height);

Please help me out.

Answer 1

I could figure it out by myself. It was a realy old driver. With newest driver the logitech webcam found both cams and both can be changed in resolution. Why skype could shange resolution down and opencv doesn't -> i couldn't figure this out. AND it looked like that the first frame was correct, maybe before loading the second camera?!, it changed to this cutted image. Thanks to rotating_image for trying to help.