[学习OpenCV攻略][010][写入AVI文件]

cvSize(文件宽度,文件高度)

通过图片或视频文件的宽高得到尺寸信息，返回值是CvSize

cvCreateVideoWriter(输出文件名,编码格式,帧率,图像大小)

通过设置输出视频的格式信息得到输出的视频，返回值是CvVideoWriter

CV_FOURCC(编码格式)

设置编码格式，('D','X','5','0') mpeg4格式，('M','J','P','G') mjpeg

cvWriteToAVI(输出视频流,输入视频流)

将输出视频流（IplImage类型）写成AVI格式到输出视频流（CvVideoWriter类型）中

cvReleaseVideoWriter(视频写入器)

释放视频写入器

#include <stdio.h>
#include "cv.h"
#include "highgui.h"
 
int main(int argc, char **argv){
    cvNamedWindow("hello", CV_WINDOW_AUTOSIZE);
    cvNamedWindow("log_polar", CV_WINDOW_AUTOSIZE);
     
    CvCapture *capture = cvCreateFileCapture(argv[1]);
    if(!capture){
        return -1;
    }
     
    double fps = cvGetCaptureProperty(capture, CV_CAP_PROP_FPS);
    printf("fps = %d\n", (int)fps);
     
    CvSize size = cvSize(
        (int)cvGetCaptureProperty(capture, CV_CAP_PROP_FRAME_WIDTH),
        (int)cvGetCaptureProperty(capture, CV_CAP_PROP_FRAME_HEIGHT)
    );
    printf("frame (w,h) = (%d,%d)\n", size.width, size.height);
     
    CvVideoWriter *write = cvCreateVideoWriter(argv[2], CV_FOURCC('M','J','P','G'), fps, size);   //CV_FOURCC('D','X','5','0') mpeg格式 CV_FOURCC('M','J','P','G') mjpeg格式
     
    IplImage *logpolar_frame = cvCreateImage(size, IPL_DEPTH_8U, 3);
    IplImage *gray_frame = cvCreateImage(size, IPL_DEPTH_8U, 1);
     
    IplImage *bgr_frame;
    while(1){
        bgr_frame = cvQueryFrame(capture);
        if(!bgr_frame){
            break;
        }
         
        cvShowImage("hell0", bgr_frame);
         
        cvConvertImage(bgr_frame, gray_frame, CV_RGB2GRAY);
         
        cvLogPolar(
            bgr_frame, 
            logpolar_frame, 
            cvPoint2D32f(bgr_frame->width/2,bgr_frame->height/2), 
            40, 
            CV_INTER_LINEAR+CV_WARP_FILL_OUTLIERS
        );
        cvShowImage("log_polar", logpolar_frame);
         
        cvWriteToAVI(write, logpolar_frame);   //输出的文件名为.avi格式
         
        char c = cvWaitKey(10);
        if(c == 27){
            break;
        }
    }
     
    cvReleaseVideoWriter(&write);
    cvReleaseImage(&gray_frame);
    cvReleaseImage(&logpolar_frame);
    cvReleaseCapture(&capture);
    cvDestroyWindow("hello");
    cvDestroyWindow("log_polar");
     
    return 0;
}