#include <iostream>
 
// ダミーのクラス群
class Mat{
public:
    int m_frame;
    Mat(int frame=-1):m_frame(frame){}
};
class VideoCapture{
public:
    int m_frame;
    VideoCapture():m_frame(0){}
    VideoCapture& operator>>( Mat &m){ m = m_frame++; return *this;}
};
class VideoWriter{
public:
    int m_frame;
    VideoWriter():m_frame(0){}
    VideoWriter & operator<<(const Mat &m){
        std::cout << "dst[" << m_frame << "],src[" << m.m_frame << "]" << std::endl;
        m_frame++;
        return *this;
    }
};
 
// ratio倍速のフレーム画像を取得
Mat getImage( VideoCapture &src, int ratio)
{
    // 倍速＝間引いて取得する
    Mat frame(-1);
    for( int i = 0; i < ratio; i++){
        src >> frame;
    }
    return frame;
}
 
int main() {
    VideoCapture video;
    VideoWriter writer;
    Mat frame = getImage( video, 1);
    for( int i = 0; i < 60; i++){
        // 10frameごとに0,1,2...倍速の画像を書き込む
        int ratio = i / 10;
        if( i % 10 == 0){
            std::cout << "ratio=" << ratio << std::endl;
        }
        if( ratio > 0){	// 0倍速＝取得不要
            frame = getImage( video, ratio);
        }
        writer << frame;
    }
    return 0;
}

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