capture-frame.cpp

opencv codes in C++ (linux and eclipse)

/* program to capture 100th frame from video and display the 100th frame in the image.
   When the frame reaches the 100th frame, its is saved in another image */

#include "cv.h"
#include "cvaux.h"
#include "highgui.h"
#include <stdio.h>

int main( int argc, char** argv )
{	
		/* capture video from file*/
	CvCapture* capture = cvCaptureFromFile("out.avi"); 
	IplImage* img = 0; 
	
	cvNamedWindow("Original Image",1);
	cvNamedWindow("100th Frame",1);
	

	
	if(!cvGrabFrame(capture))
	{              // capture a frame 
  		printf("Could not grab a frame !!! \n");
  		exit(0);
	}
	
	int key;
	int numFrames; 

	
	for (;;) 
		{
			img=cvRetrieveFrame(capture); 
			if (!img) 
				{
					break;
				}
			if(cvGrabFrame(capture))
				{ 
					
					numFrames = (int)(cvGetCaptureProperty(capture, CV_CAP_PROP_POS_FRAMES));
					printf("Frame: %d\n",numFrames);
					//img=cvRetrieveFrame(capture);  
					cvShowImage("Original Image", img); 
					cvMoveWindow("100th Frame",500,0);
		
					if ( numFrames == 100 )
					{ 
			  			cvSaveImage("resultant image of 100th frame.jpg",img);
  						cvShowImage("100th Frame",img);
  			  	    }
	  				else 
  					key = cvWaitKey(400);
			   }
		  else
			  {
				printf("reached at the end of the frame!!!!\n");
				exit(0);
			  }
  	}
	cvWaitKey(0);
	cvReleaseCapture(&capture);
	return 0;  
}