OpenCV: Present a video file

#include "chapter2.h"

void display_video(char **argv)
{
	// CvCapture structure is used to store the information of the various properties of the
	// avi and the create file capture returns a pointer of this type initialized to the beginning
	// of the avi
	CvCapture *pCapture = cvCreateFileCapture(argv[1]);

	// Create a window to display the video frames
	cvNamedWindow("2. Present a video", CV_WINDOW_AUTOSIZE );

	// We will be reading information frame by frame. This memory is a part of the CvCapture structure and
	// we need to create a temporary pointer to point to it.
	IplImage *pFrame;

	// Get the frame fps
	int fps = (int) cvGetCaptureProperty(pCapture, CV_CAP_PROP_FPS);
	cout<<"The video fps:"<<fps<<endl;
	// We create an infinite loop to read in frames one by one till either the user hits escape or
	// the file reaches an end.
	while(1)
	{
		// Read in one frame at a time. Thus frame image returned is a part of the memory allocated to the cvCapture
		// Since this is memory of the CvCapture we dont need to deallocate(cvReleaseImage) this memory.
		pFrame = cvQueryFrame(pCapture);

		// If the end of file is reached the queryFrame will return a null
		if (!pFrame)break;

		// Show the frame we have like we normally do
		cvShowImage("2. Present a video", pFrame);

		// Now we have a time gap of approx (1000/fps) ms before we need to show the next frame
		char wait = cvWaitKey(1000/fps);
		// If the esc key was hit then we break out. Esc => 27 in ASCII
		if (wait == 27)break;
	}

	// Now we proceed to release the capture data and destroy the window
	cvReleaseCapture(&pCapture);
	cvDestroyWindow("2. Present a video");
}