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MP4轉.JPG

#include<opencv2\opencv.hpp>
#include <iostream>
#include <stdio.h>
#include<fstream> 

using namespace std;
using namespace cv;

//獲取視訊中的人臉

int main()
{
    //開啟視訊檔案:其實就是建立一個VideoCapture結構  
    VideoCapture capture("new.mp4");
    //檢測是否正常開啟:成功開啟時,isOpened返回ture  
    if (!capture.isOpened())
        cout
<< "fail toopen!" << endl; //獲取整個幀數 long totalFrameNumber = capture.get(CV_CAP_PROP_FRAME_COUNT); cout << "整個視訊共" << totalFrameNumber << "幀" << endl; //設定開始幀() long frameToStart = 1; capture.set(CV_CAP_PROP_POS_FRAMES, frameToStart); cout
<< "從第" << frameToStart << "幀開始讀" << endl; //設定結束幀 int frameToStop = totalFrameNumber; if (frameToStop < frameToStart) { cout << "結束幀小於開始幀,程式錯誤,即將退出!" << endl; return -1; } else { cout << "結束幀為:第" << frameToStop << "幀"
<< endl; } //獲取幀率 double rate = capture.get(CV_CAP_PROP_FPS); cout << "幀率為:" << rate << endl; //定義一個用來控制讀取視訊迴圈結束的變數 bool stop = false; //承載每一幀的影象 Mat frame; //顯示每一幀的視窗 namedWindow("Extractedframe"); //兩幀間的間隔時間: //int delay = 1000/rate; double delay = 1000 / rate; //利用while迴圈讀取幀 //currentFrame是在迴圈體中控制讀取到指定的幀後迴圈結束的變數 long currentFrame = frameToStart; //濾波器的核 int kernel_size = 3; Mat kernel = Mat::ones(kernel_size, kernel_size, CV_32F) / (float)(kernel_size*kernel_size); while (!stop) { //讀取下一幀 if (!capture.read(frame)) { cout << "讀取視訊失敗" << endl; return -1; } cout << "正在讀取第" << currentFrame << "幀" << endl; imshow("Extractedframe", frame); cout << "正在寫第" << currentFrame << "幀" << endl; stringstream str; str << "face//"<<currentFrame << ".jpg"; cout << str.str() << endl; //waitKey(intdelay=0)當delay≤ 0時會永遠等待;當delay>0時會等待delay毫秒 //當時間結束前沒有按鍵按下時,返回值為-1;否則返回按鍵 //int c = waitKey(delay); int c = waitKey(10); //按下ESC或者到達指定的結束幀後退出讀取視訊 if ((char)c == 27 || currentFrame > frameToStop) { stop = true; } //按下按鍵後會停留在當前幀,等待下一次按鍵 if (currentFrame % 5==0) imwrite(str.str(), frame); currentFrame = currentFrame + 1; } //關閉視訊檔案 capture.release(); return 0; }