Opencv保存视频

Question

我正在使用级联检测对象，我想在检测后保存我的视频但我只能保存一帧（我只能保存最后一帧） 我的代码在这里：

#include <opencv2/highgui/highgui.hpp>
#include <opencv2/imgproc/imgproc.hpp> 
#include <iostream>
#include <stdio.h>
#include <opencv2/objdetect/objdetect.hpp>
using namespace std;
using namespace cv;
int main()
{
CascadeClassifier nesne;
nesne.load("cascade.xml");
string filename = "a.avi";
    VideoCapture capture(filename);

Mat frame;
Mat grires;
namedWindow("algilanan", 1);

while(true)
{
capture>>frame;
cvtColor(frame, grires, CV_BGR2GRAY);  //resmi gri renk uzayına çevirir. 
vector<Rect> nesvek;
nesne.detectMultiScale(grires, nesvek, 1.1, 3, 0, Size(30,30));
for(int i = 0; i < nesvek.size(); i++)
{
Point pt1(nesvek[i].x + nesvek[i].width, nesvek[i].y + nesvek[i].height);
Point pt2(nesvek[i].x, nesvek[i].y);
rectangle(frame, pt1, pt2, cvScalar(0, 255, 0, 0), 1, 8, 0);

}
int frame_width=   capture.get(CV_CAP_PROP_FRAME_WIDTH);
int frame_height=   capture.get(CV_CAP_PROP_FRAME_HEIGHT);
VideoWriter video("out.avi",CV_FOURCC('M','J','P','G'),10, Size(frame_width,frame_height),true);
video.write(frame);
imshow("algilanan", frame);
waitKey(33);

}
return 0;
}

Answer 1

您可以保存单个帧的原因是因为您在循环的每次迭代中都重新初始化了VideoWriter。您应该在循环外对其进行初始化。试试这个。

#include <opencv2/highgui/highgui.hpp>
#include <opencv2/imgproc/imgproc.hpp> 
#include <iostream>
#include <stdio.h>
#include <opencv2/objdetect/objdetect.hpp>
using namespace std;
using namespace cv;
int main()
{
CascadeClassifier nesne;
nesne.load("cascade.xml");
string filename = "a.avi";
VideoCapture capture(filename);

Mat frame;
Mat grires;
namedWindow("algilanan", 1);

int frame_width=   capture.get(CV_CAP_PROP_FRAME_WIDTH);
int frame_height=  capture.get(CV_CAP_PROP_FRAME_HEIGHT);
VideoWriter video("out.avi",CV_FOURCC('M','J','P','G'),10,Size(frame_width,frame_height),true);

while(true)
{
capture>>frame;
cvtColor(frame, grires, CV_BGR2GRAY);  //resmi gri renk uzayına çevirir. 
vector<Rect> nesvek;
nesne.detectMultiScale(grires, nesvek, 1.1, 3, 0, Size(30,30));
for(int i = 0; i < nesvek.size(); i++)
{
Point pt1(nesvek[i].x + nesvek[i].width, nesvek[i].y + nesvek[i].height);
Point pt2(nesvek[i].x, nesvek[i].y);
rectangle(frame, pt1, pt2, cvScalar(0, 255, 0, 0), 1, 8, 0);
}  
video.write(frame);
imshow("algilanan", frame);
waitKey(33);

}
return 0;
}