实现读入一个彩色视频文件并以灰度格式输出这个视频文件,学习opencv例2-10

#include "cv.h"
#include "highgui.h"
int main(int argc,char* argv[]){ //书本中的main没有定义为int返回类型，就会报错：c++默认不支持int
CvCapture* capture = 0;
capture = cvCreateFileCapture("p.avi");//p.avi直接存放在当前cpp文件所在的文件夹下，所有不用写路径，否则如：D:\\sandy\\visual studio 2010\\Projects\\video\\video\\p.avi
if(!capture) 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),
(int)cvGetCaptureProperty(capture,CV_CAP_PROP_FRAME_HEIGHT)
);
CvVideoWriter *writer=cvCreateVideoWriter("d:\\shengcheng.avi",CV_FOURCC('M','J','P','G'),fps,size);//把CV_FOURCC('M','J','P','G')改为-1，就在d盘生成一个shengcheng.avi文件了，我也没搞懂为什么
IplImage* logpolar_frame =cvCreateImage(size,IPL_DEPTH_8U,3);

while((bgr_frame = cvQueryFrame(capture))!=NULL){
cvLogPolar(bgr_frame,logpolar_frame,
cvPoint2D32f(bgr_frame->width/2,
bgr_frame->height/2),
40,CV_INTER_LINEAR+CV_WARP_FILL_OUTLIERS);
cvWriteFrame(writer,logpolar_frame);
}
cvReleaseVideoWriter(&writer);
cvReleaseImage(&logpolar_frame);
cvReleaseCapture(&capture);
return(0);
}

原视频：

生成视频：