Learning OpenCV: cvPyrDown and display video

视频处理与缩放

最新推荐文章于 2024-10-05 14:51:41 发布

原创最新推荐文章于 2024-10-05 14:51:41 发布 · 308 阅读

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本文介绍了一个使用OpenCV进行视频文件读取，并实现视频帧缩放及显示的应用案例。通过创建窗口、设置滑块来控制视频播放位置，同时利用金字塔算法进行图像下采样处理，展示了如何将视频帧按比例缩小并实时显示。

#include "stdafx.h"
#include <iostream>
#include <fstream>
using namespace std;
#include "cv.h"
#include "highgui.h"
#include <assert.h>

int g_slider_position = 0;
CvCapture * g_capture = NULL;

void onTrackbarSlide(int pos)
{
cvSetCaptureProperty(g_capture,CV_CAP_PROP_POS_FRAMES,pos);
}

int main(void)
{
cvNamedWindow("video",CV_WINDOW_AUTOSIZE);
g_capture = cvCreateFileCapture("E:\\test\\fish1.avi");
int frames = (int)cvGetCaptureProperty(g_capture,CV_CAP_PROP_FRAME_COUNT);
if(frames != 0)
{
cvCreateTrackbar("position","video",&g_slider_position,frames,onTrackbarSlide);
}
IplImage * frame = NULL;
frame = cvQueryFrame(g_capture);
if(g_capture == NULL)
{
cout<<"read video file error!"<<endl;
}
IplImage * outFrame = NULL;
assert(frame->width%2==0 && frame->height%2==0);
outFrame = cvCreateImage(cvSize(frame->width/2,frame->height/2),frame->depth,frame->nChannels);
cvNamedWindow("outvideo",CV_WINDOW_AUTOSIZE);
while(1)
{
frame = cvQueryFrame(g_capture);
if(frame == NULL)
{
break;
}
cvShowImage("video",frame);
//cvSmooth(frame,outFrame,CV_GAUSSIAN,3);
cvPyrDown(frame,outFrame,IPL_GAUSSIAN_5x5);
cvShowImage("outvideo",outFrame);
char c = cvWaitKey(33);
if(c == 27)
{
break;
}
}
cvReleaseCapture(&g_capture);
g_capture = NULL;
cvDestroyWindow("video");
cvDestroyWindow("outvideo");
cvReleaseImage(&outFrame);
outFrame = NULL;
return 0;
}