opencv-视频输出

#include <iostream>// for standard I/O#include <string>   // for strings#include <opencv2/core/core.hpp>        // Basic OpenCV structures (cv::Mat)#include <opencv2/highgui/highgui.hpp>  // Video writeusing namespace std;using namespace cv;void help(){    cout        << "\n--------------------------------------------------------------------------" << endl        << "This program shows how to write video files. You can extract the R or G or B color channel "        << " of the input video.write "  << endl        << "Usage:"                                                               << endl        << "./video-write inputvideoName [ R | G | B] [Y | N]"                   << endl        << "--------------------------------------------------------------------------"   << endl        << endl;}int main(int argc, char *argv[], char *window_name){    help();    if (argc != 4)    {        cout << "Not enough parameters" << endl;        return -1;    }    const string source      = argv[1];           // 输入视频名字    const bool askOutputType = argv[3][0] =='Y';  // If false it will use the inputs codec type    VideoCapture inputVideo(source);        //打开输入视频    if ( !inputVideo.isOpened())    {        cout  << "Could not open the input video." << source << endl;        return -1;    }    string::size_type pAt = source.find_last_of('.');   // 查找扩展点    const string NAME = source.substr(0, pAt) + argv[2][0] + ".avi";   // 生成存储器的新名字    int ex = static_cast<int>(inputVideo.get(CV_CAP_PROP_FOURCC));     // 获得编解码类型    // 比特操作把int转换为char    char EXT[] = {ex & 0XFF , (ex & 0XFF00) >> 8,(ex & 0XFF0000) >> 16,(ex & 0XFF000000) >> 24, 0};    Size S = Size((int) inputVideo.get(CV_CAP_PROP_FRAME_WIDTH),    //获得输入视频大小                  (int) inputVideo.get(CV_CAP_PROP_FRAME_HEIGHT));    VideoWriter outputVideo;                                        //打开输出视频    if (askOutputType)            outputVideo.open(NAME  , ex=-1, inputVideo.get(CV_CAP_PROP_FPS),S, true);    else        outputVideo.open(NAME , ex, inputVideo.get(CV_CAP_PROP_FPS),S, true);    if (!outputVideo.isOpened())    {        cout  << "Could not open the output video for write: " << source << endl;        return -1;    }    union { int v; char c[5];} uEx ;    uEx.v = ex;                              // 通过union函数，把char转换为int    uEx.c[4]='\0';    cout << "Input frame resolution: Width=" << S.width << "  Height=" << S.height        << " of nr#: " << inputVideo.get(CV_CAP_PROP_FRAME_COUNT) << endl;    cout << "Input codec type: " << EXT << endl;    int channel = 2;    // 选择保存通道 B,R,G    switch(argv[2][0])    {    case 'R' : {channel = 2; break;}    case 'G' : {channel = 1; break;}    case 'B' : {channel = 0; break;}    }    Mat src,res;    vector<Mat> spl;    while( true) //Show the image captured in the window and repeat    {        inputVideo >> src;              // read        if( src.empty()) break;         // check if at end       split(src, spl);                 // process - extract only the correct channel       for( int i =0; i < 3; ++i)        if (i != channel)           spl[i] = Mat::zeros(S, spl[0].type());       merge(spl, res);       //outputVideo.write(res); //save or       outputVideo << res;    }    cout << "Finished writing" << endl;    return 0;}