USB Camera capture is slow

Hi! I'm trying to capture the image from my USB camera but it is slow (about 6 fps) due to the pixel format chosen by OpenCV for capturing. My camera supports YUYV format and MJPEG format (which can provide the 30 fps) but OpenCV only use the first format. What can I do for opening my camera with MJPG format in OpenCV ? Or should I use another method, have you an advice on which one ? Thank you! BTW I'm running OpenCV 3.2.0 with linux if there is a link with this problem.