title: Read image from URL for openCV input
body: <p>I want to read from IP camera with openCV, IP camera provides a RTSP output rtsp://ip:port/video.3gp but <code>cvCaptureFromFile("rtsp://ip:port/video.3gp");</code> shows a blank screen, the alternative solution is using using JPEG output, its url is <a href="http://ip/jpg/image.jpg">http://ip/jpg/image.jpg</a> and will every 50ms, but also <code>cvCaptureFromFile("http://ip/jpg/image.jpg");</code> returns blank screen; I dont't know do I use it in right way or not.</p>