video-capture

Code: Simple example that works perfectly with primary webcam (device 0): VideoCapture cap(0); if (!cap.isOpened()) { std::cout << "Unable to read stream from specified device." << std::endl; return; } while (true) { // retrieve the frame: Mat frame; if (!cap.read(frame)) { std::cout << "Unable to retrieve frame from video stream." << std::endl; break; } // display it: imshow("MyVideo", frame); // check if Esc has been pressed: if (waitKey(1) == 27) { break; } // else continue: } cap.release(); Problem: I have a second webcam, which I'd like to use. However, when I replace VideoCapture cap(0);

I am having Assertion failed error at the last frame , while reading and writing a video frame by frame. The errors only shows at the last frame, don't know why. saw this answer here , whichs suggests to give waitkey, my code already have wait key on it. my simple code is as follows int main() { CvCapture *capture=cvCaptureFromFile("C:\\vid\\op.mp4"); if(capture==NULL) { printf("can't open video"); } Mat frame, first_frame,current_frame; char buffer[100]; int frame_count=1,p=1; while(1) { /*Getting the current frame from the video*/ frame=cvQueryFrame(capture); cv::cvtColor(frame,current_frame

I found similar questions in stackoverflow. But I want to be specific. I visited a web site screencast-o-matic . They have a web-application of java applet which capture screen to export as video. I want to develop similar application. What are the knowledge and steps required to do it? Thanks and regards. Edit another website screenr . Andrew Thompson To get a screenshot, use Robot.createScreenCapture(Rectangle) . To get many screenshots, call that in a loop invoked by a (Swing) Timer . Add them to an expandable collection such as an ArrayList . Convert the BufferedImage objects to JPEG

Context: I have been playing around with python's wrapper for opencv2. I wanted to play with a few ideas and use a wide angle camera similar to 'rear view' cameras in cars. I got one from a scrapped crash car (its got 4 wires) I took an educated guess from the wires color codding, connect it up so that I power the power and ground line from a usb type A and feed the NTSC composite+ composite- from an RCA connector. I bought a NTSC to usb converter like this one . It came with drivers and some off the shelf VHStoDVD software. the problem: I used the run of the mill examples online to trial test