OpenCV写入AVI视频文件

本文只是简单的写入AVI视频文件的代码，通过调用cvWriteFrame（）逐帧将视频流写入文件。写入结束后，我们调用cvReleaseVideoWriter（）来释放资源。这个程序首先打开一个视频文件，读取文件内容，将每一帧图像转换为对数极坐标格式，最后将转化后的图像序列写入新的视频文件中。

#include "cv.h"
#include "highgui.h"
#include <stdio.h>

// Convert a video to grayscale
// argv[1]: input video file
// argv[2]: name of new output file
//

//#define NOWRITE 1;   //Turn this on (removed the first comment out "//" if you can't write on linux

void main(  ) {
cvNamedWindow( "Example2_10", CV_WINDOW_AUTOSIZE );
cvNamedWindow( "Log_Polar", CV_WINDOW_AUTOSIZE );
CvCapture* capture = cvCreateFileCapture("G:/数据/OpenCV数据/song.mp4" );
//if (!capture){
//    return -1;
//}
IplImage* bgr_frame;
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);
#ifndef NOWRITE
CvVideoWriter* writer = cvCreateVideoWriter(
"G:/数据/OpenCV数据/wind2.avi",
CV_FOURCC('M','J','P','G'),
fps,
size
);
#endif
IplImage* logpolar_frame = cvCreateImage(
size,
IPL_DEPTH_8U,
3
);

IplImage* gray_frame = cvCreateImage(
size,
IPL_DEPTH_8U,
1
);

while( (bgr_frame=cvQueryFrame(capture)) != NULL ) {
cvShowImage( "Example2_10", bgr_frame );
//We never make use of this gray image
cvConvertImage(
bgr_frame,
gray_frame,
CV_RGB2GRAY
);
//This is just a fun conversion the mimic's the human visual system
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 );
//Sigh, on linux, depending on your ffmpeg, this often won't work ...
#ifndef NOWRITE
cvWriteToAVI( writer, logpolar_frame );
#endif
char c = cvWaitKey(10);
if( c == 27 ) break;
}
#ifndef NOWRITE
cvReleaseVideoWriter( &writer );
#endif
cvReleaseImage( &gray_frame );
cvReleaseImage( &logpolar_frame );
cvReleaseCapture( &capture );
}

初次接触视频编码，现简单介绍一下视频编码：

所谓视频编码方式就是指通过特定的压缩技术，将某个视频格式的文件转换成另一种视频格式文件的方式。视频流传输中最为重要的编解码标准有国际电联的H.261、H.263、H.264，运动静止图像专家组的M-JPEG和国际标准化组织运动图像专家组的MPEG系列标准，此外在互联网上被广泛应用的还有Real-Networks的RealVideo、微软公司的WMV以及Apple公司的QuickTime等。

文章引用：百度百科

http://baike.baidu.com/link?url=9o3OWcVriiyEwLdIiIspcGbT_aAZ-Po2nmy2S1-kQUBEPP2FiqMjHN14KWKQe8V6e3g0n3kCMrzt2AB-O1j9_q