I am using video4linux API with a USB1.1 ov511 Webcam. The image
capture performance appeared to be very slow, so I timed how long the
call to "ioctl(VIDIOSYNC)" was taking. It took 930 ms (almost 1
second) to capture 1 frame of 640x480 pixels and 230ms to capture 1
frame of 320x240 pixels. I am setting the palette to
VIDEO_PALETTE_YUV420P and am using mmap() to map video memory to
system memory. Is this typical? Or is this very slow? How can I speed
things up (other than double buffering).