[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
", (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)
", 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;
}