【opencv课后练习】-- 第二章节

      网上查了下，没能找到关于learning opencv的课后习题讲解，现张贴出自我学习过程的code，与广大Coder共同探讨学习，多多指出小弟的错误，谢谢。

题目：使用例2-10中的视频捕捉和存储方法，结合例2-5中的doPyrDown()创建一个程序，使其从摄像机读入视频数据并将缩放变换后的彩色图像存入磁盘。

/*
	使用例2-10中的视频捕捉和存储方法，结合例2-5中的doPyrDown()创建一个程序，
	使其从摄像机读入视频数据并将缩放变换后的彩色图像存入磁盘
	chapter2-3
*/
#include <opencv2/core/core.hpp>                  
#include <opencv2/highgui/highgui.hpp>                  
#include <opencv2/imgproc/imgproc.hpp>   
#include <cv.h>  
#include <iostream>                
using namespace std;  
using namespace cv;
IplImage *doPyrDown(IplImage * in)
{
	IplImage* out = cvCreateImage(
		cvSize(in->width/2,in->height/2),
		in->depth,
		in->nChannels
		);
	//借用下opencv1 中的cvPyrDown函数修改frame尺寸
	cvPyrDown(in,out,CV_GAUSSIAN_5x5);
	return out;
}

int main (int argc,char* argv[])
{
	
	CvCapture* capture = cvCreateFileCapture("D:\\123.avi");
	if(!capture)
	{
		cout<<"Fail to open!"<<endl;
		return -1;
	}
	IplImage* bgr_frame = cvQueryFrame(capture);
	double fps = cvGetCaptureProperty(capture,CV_CAP_PROP_FPS);
	CvSize size = cvSize(
		(int)cvGetCaptureProperty(capture,CV_CAP_PROP_FRAME_WIDTH)/2,
		(int)cvGetCaptureProperty(capture,CV_CAP_PROP_FRAME_HEIGHT)/2
		);
	CvVideoWriter *writer = cvCreateVideoWriter(
		"2.avi",
		CV_FOURCC('M','J','P','G'),
		fps,
		size
		);
	IplImage * logpolar_frame = cvCreateImage(
		size,
		IPL_DEPTH_8U,
		3
		);
	while( (bgr_frame = cvQueryFrame(capture)) != NULL )
	{
		IplImage* out =  doPyrDown(bgr_frame);
		cvWriteFrame(writer,out);
	}
	cvReleaseVideoWriter(&writer);
	cvReleaseImage(&logpolar_frame);
	cvReleaseCapture(&capture);
	return 0;
	
}