VideoWriter not working on Win7-64Bit VM

问题

I coded the below which tries to hold a picture and count number hundred and finally grab all them to a video with following codec MP42(MPEG4-V2)

#include <stdAfx.h>
#include <iostream>
#include <opencv2\opencv.hpp>

using namespace cv;
using namespace std;
int n=0;
char a;
int main(int, char** argv)
{
    Mat image= imread("C:\\Users\\Metin\\Desktop\\images.jpg");
    Mat newimage;
    VideoWriter vide ("Hopdedik.avi",CV_FOURCC('M','P','4','2'),30.0,image.size());
    vide.open("Hopdedik.avi",CV_FOURCC('M','P','4','2'),30.0,image.size()); 
    for(int n=0; n<100;n++){
        cout<<n<<'\n';
        std::string s= to_string(static_cast<long long>(n));
        image.copyTo(newimage);
        putText(newimage,s,Point(100,40),cv::FONT_HERSHEY_COMPLEX,2,cv::COLORMAP_COOL,2,2,false);
        imshow("asd",newimage);     
        if(!vide.isOpened())cout<<"can not opened";     
        vide.write(newimage);
        waitKey(10);        
    }
    vide.release(); 
    return 0;
}

I started debugging on Release mode and copied the .exe files to Virtualbox Win7-64 bit. Right after I put necessary .dll files exe works but the code can't properly create the video.

I have tried to install following two codecs: http://www.fourcc.org/downloads/angel-potion-mpeg-4--8/ and Indeo which is: http://www.afreecodec.com/codec-by-code/iv45-160.html

But it did not work.

回答1:

Once I faced a similar problem where opencv couldn't read a video. There was no warning at all. The reason was that an automated string maker resulted in "opencv_mmpeg.dll" which was missing from the system. So, I debugged up to cap_ffmpeg.cpp and found this:

#if defined WIN32 || defined _WIN32
    const char* module_name = "opencv_ffmpeg"
        CVAUX_STR(CV_MAJOR_VERSION) CVAUX_STR(CV_MINOR_VERSION) CVAUX_STR(CV_SUBMINOR_VERSION)
    #if (defined _MSC_VER && defined _M_X64) || (defined __GNUC__ && defined __x86_64__)
        "_64"
    #endif
        ".dll";

So, copy opencv_ffmpeg_64.dll to your folder and you might have some results. Else, you need to debug deeply. Start by inserting into your project the file opencv/modules/highgui/src/cap.cpp (and the headers needed to be compiled) so you can debug line by line. I suppose many other files will be needed to go further down into the code.

来源：https://stackoverflow.com/questions/17573919/videowriter-not-working-on-win7-64bit-vm

标签

c++

OpenCV

windows-7-x64

codec