opencv 读取视频中的每一帧

来源：互联网发布：男风时尚生活知乎编辑：程序博客网时间：2024/05/16 11:48

// test3.cpp
//
// 该程序实现视频和图片的相互转换.
// Image_to_video()函数将一组图片合成AVI视频文件.
// Video_to_image()函数将AVI视频文件读入，将每一帧存储为jpg文件.
//
////////////////////////////////////////////////////////////////////////
#include <stdlib.h>
#include <stdio.h>
#include <math.h>
#include <cv.h>
#include <highgui.h>

#define NUM_FRAME 300 //只处理前300帧，根据视频帧数可修改

void Video_to_image(char* filename)
{
printf("------------- video to image ... ----------------\n");

//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 : %d\n\tvideo width : %d\n\tfps : %d\n\tframe numbers : %d\n", frameH, frameW, fps, numFrames);

//定义和初始化变量
int i = 0;
IplImage* img = 0;
char image_name[13];

cvNamedWindow( "mainWin", CV_WINDOW_AUTOSIZE );

//读取和显示
while(1)
{

   img = cvQueryFrame(capture); //获取一帧图片
   cvShowImage( "mainWin", img ); //将其显示
   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;
}

cvReleaseCapture(&capture);
cvDestroyWindow("mainWin");
}

void Image_to_video()
{
int i = 0;
IplImage* img = 0;
char image_name[13];

printf("------------- image to video ... ----------------\n");

//初始化视频编写器，参数根据实际视频文件修改
CvVideoWriter *writer = 0;
int isColor = 1;
int fps = 30; // or 25
int frameW = 400; // 744 for firewire cameras
int frameH = 240; // 480 for firewire cameras
writer=cvCreateVideoWriter("out.avi",CV_FOURCC('X','V','I','D'),fps,cvSize(frameW,frameH),isColor);

printf("\tvideo height : %d\n\tvideo width : %d\n\tfps : %d\n", frameH, frameW, fps);

//创建窗口
cvNamedWindow( "mainWin", CV_WINDOW_AUTOSIZE );

while(i<NUM_FRAME)
{
   sprintf(image_name, "%s%d%s", "image", ++i, ".jpg");
   img = cvLoadImage(image_name);
   if(!img)
   {
    printf("Could not load image file...\n");
    exit(0);
   }
   cvShowImage("mainWin", img);
   char key = cvWaitKey(20);

cvWriteFrame(writer, img);
}

cvReleaseVideoWriter(&writer);
cvDestroyWindow("mainWin");
}

int main(int argc, char *argv[])
{

char filename[13] = "infile.avi";

Video_to_image(filename); //视频转图片

Image_to_video(); //图片转视频

return 0;
}
//------------------

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