C++实现视频流转换为图片方式

/*  avi2jpg 函数，将摄像头当前帧保存为jpg格式照片 */
  
void Video_to_image(CvCapture* capture)
{
    //初始化一个视频文件捕捉器
    //CvCapture* capture = cvCaptureFromAVI(filename);
    //获取视频信息
    cvQueryFrame(capture);
    /*
    int frameH  = (int) cvGetCaptureProperty(capture, CV_CAP_PROP_FRAME_HEIGHT);
    int frameW  = (int) cvGetCaptureProperty(capture, CV_CAP_PROP_FRAME_WIDTH);
    int fps    = (int) cvGetCaptureProperty(capture, CV_CAP_PROP_FPS);
    int numFrames = (int) cvGetCaptureProperty(capture, CV_CAP_PROP_FRAME_COUNT);
    //printf("tvideo height : %dntvideo width : %dntfps : %dntframe numbers : %dn", frameH, frameW, fps, numFrames);
    */
    //定义和初始化变量
    int i = 0;
    IplImage* img = 0;
    char image_name[13] = "1";
    //读取和显示
    while(1)
    {
        img = cvQueryFrame(capture); //获取一帧图片
        char key = cvWaitKey(20);
        sprintf(image_name, "%s%d%s", "image", ++i, ".jpg");//保存的图片名
        cvSaveImage( image_name, img);  //保存一帧图片
        if(i == NUM_FRAME) break;
    }
}