WebCam won't open since 2.4.6 (Bug #3141)

Hi,

I'm using VideoCapture to connect to my webcam in the following manner since OpenCV2.4.4:

cv::VideoCapture vcap;
cv::Mat image;
...
vcap.open(CV_CAP_ANY);
if(vcap.isOpened()){
while(m_runGrabber){
vcap >> image;
}
}
...

and never had any problems. Since version 2.4.6 though, opening my cam fails and isOpened() always returns false. When I downgrade to 2.4.5 it works again. Also loading a video with 2.4.6 works, so the reason seems to be the combination of 2.4.6 and the webcam. I also tried to open the cam with the constructor. cv::VideoCapture vcap(CV_CAP_ANY). It didn't work either. There is also no other camera connected, so CV_CAP_ANY should work as it did with version 2.4.5

I played around and rebuild the OpenCV with different options (almost every possible combination of using XINE, XIMEA, V4L, UNICAP, TBB, 1394, PVAPI) , but neither did fix my problem. However when UNICAP is used I get another strange effect: the camera can be openend (at least I see the green light of my webcam turned on), but it completly blocks the application, once I start grabbing.

I again like to note, that when switching to 2.4.5 or 2.4.4, everything works perfect as before.

I'm using Kubuntu 12.04 and g++4.6.3 and Logitech C270 USB HD Webcam. The camera worked by plug & play, so i guess some standard drivers are used. If someone can explain me how, I would check which driver is used exactly;)

If any other information is needed, I'l gladly provide.