从文件opencv读取视频

Question

嗨所以我写了这段代码来捕获文件中的视频

#include <stdio.h>
#include <cv.h>
#include "highgui.h"
#include <iostream>

//using namespace cv

int main(int argc, char** argv)
{
    CvCapture* capture=0;
    IplImage* frame=0;
    capture = cvCaptureFromAVI(char const* filename); // read AVI video    
    if( !capture )
        throw "Error when reading steam_avi";

    cvNamedWindow( "w", 1);
    for( ; ; )
    {
        frame = cvQueryFrame( capture );
        if(!frame)
            break;
        cvShowImage("w", frame);
    }
    cvWaitKey(0); // key press to close window
    cvDestroyWindow("w");
    cvReleaseImage(&frame);
}

每次我运行它,我都会收到以下错误:

CaptureVideo.cpp:在函数'int main(int,char**)'中:

CaptureVideo.cpp:13:28:错误:在'char'之前预期的primary-expression

任何帮助都感激不尽.

Answer 1

这是C++问题,所以你应该使用C++接口.

原始代码中的错误:

• 你忘了删除char const*在cvCaptureFromAVI.
• 您不必等待显示帧.ShowImage只有在WaitKey后面才有效.
• 我不确定capture = NULL是否意味着你的文件没有被打开.请isOpened改用.

我已经更正了你的代码并将其放入C++接口,所以它现在是一个合适的C++代码.我的重写与你的程序一样逐行.

//#include <stdio.h>
#include <opencv2/core/core.hpp>
#include <opencv2/highgui/highgui.hpp>
//#include <iostream>

using namespace cv;
using std::string;

int main(int argc, char** argv)
{
    string filename = "yourfile.avi";
    VideoCapture capture(filename);
    Mat frame;

    if( !capture.isOpened() )
        throw "Error when reading steam_avi";

    namedWindow( "w", 1);
    for( ; ; )
    {
        capture >> frame;
        if(frame.empty())
            break;
        imshow("w", frame);
        waitKey(20); // waits to display frame
    }
    waitKey(0); // key press to close window
    // releases and window destroy are automatic in C++ interface
}