来自线程的cvQueryFrame

Question

我正在尝试使用opencv（3.1.0）从单独线程中的Windows上的网络摄像头接收帧。见下面的例子。它停留在cvQueryFrame（TestThread）并且无法返回任何内容。没有错误...感谢任何帮助。谢谢！

#include <iostream>
#include "opencv2/highgui/highgui.hpp"
#include <process.h>
#include <windows.h>

void TestThread(void *param);

int main(int argc, char** argv)
{    
    CvCapture* capture;
    HANDLE handle;  
    capture = cvCaptureFromCAM(0);
    if (!capture) {     
        std::cout << "capture error";
        return -1;
    }
    IplImage* frame = cvQueryFrame( capture );
    std::cout << "main: " << frame->width;

    handle = (HANDLE) _beginthread( TestThread, 0, capture);
    WaitForSingleObject(handle,INFINITE);

    std::cout << "done";
    cvReleaseCapture(&capture);
    return 0;
}

void TestThread(void *param)
{           
    CvCapture* capture=(CvCapture*)param;
    IplImage* frame = cvQueryFrame( capture );
    std::cout << "thread: " << frame->width;
    _endthread();
}