OpenCV VideoCapture 根本无法从我的网络摄像头读取

Question

我在Ubuntu 13.04上使用OpenCV 2.4.6（在Acer C7 Chromebook上），我正在使用一个简单的测试程序来查看我的网络摄像头是否能与OpenCV配合使用。它可以与Cheese和Skype配合使用，所以我知道网络摄像头本身不是问题所在。

这是我的代码（编译时没有任何错误）：

#include "opencv2/opencv.hpp"
#include <stdio.h>
#include <stdlib.h>
using namespace std;
using namespace cv;
int main(int argc, char *argv[])
{
  cv::VideoCapture cap;
  if(argc > 1)
    {
      cap.open(string(argv[1]));
    }
  else
    {
      cap.open(CV_CAP_ANY);
    }
  if(!cap.isOpened())
    {
      printf("Error: could not load a camera or video.n");
    }
  Mat frame;
  namedWindow("video", 1);
  for(;;)
  {
    waitKey(20);
    cap >> frame;
  if(!frame.data)
    {
      printf("Error: no frame data.n");
      break;
    }
    imshow("video", frame);
  }
}

如果我在没有任何参数的情况下运行程序（因为我希望它使用CV_CAP_any），我会得到

Error: could not load a camera or video.
init done 
opengl support available 
libpng warning: Application built with libpng-1.2.49 but running with 1.5.12
libpng warning: Application built with libpng-1.2.49 but running with 1.5.12
libpng warning: Application built with libpng-1.2.49 but running with 1.5.12
libpng warning: Application built with libpng-1.2.49 but running with 1.5.12
libpng warning: Application built with libpng-1.2.49 but running with 1.5.12
libpng warning: Application built with libpng-1.2.49 but running with 1.5.12
libpng warning: Application built with libpng-1.2.49 but running with 1.5.12
libpng warning: Application built with libpng-1.2.49 but running with 1.5.12
libpng warning: Application built with libpng-1.2.49 but running with 1.5.12
libpng warning: Application built with libpng-1.2.49 but running with 1.5.12
Error: no frame data.

如果我指定/dev/video0（我唯一的相机）作为参数，我会得到

demux_wavpack: (open_wv_file:127) open_wv_file: non-seekable inputs aren't supported yet.
(ERROR)icvOpenAVI_XINE(): Unable to open source '/dev/video0'
init done 
opengl support available 
libpng warning: Application built with libpng-1.2.49 but running with 1.5.12
libpng warning: Application built with libpng-1.2.49 but running with 1.5.12
libpng warning: Application built with libpng-1.2.49 but running with 1.5.12
libpng warning: Application built with libpng-1.2.49 but running with 1.5.12
libpng warning: Application built with libpng-1.2.49 but running with 1.5.12
libpng warning: Application built with libpng-1.2.49 but running with 1.5.12
libpng warning: Application built with libpng-1.2.49 but running with 1.5.12
libpng warning: Application built with libpng-1.2.49 but running with 1.5.12
libpng warning: Application built with libpng-1.2.49 but running with 1.5.12
libpng warning: Application built with libpng-1.2.49 but running with 1.5.12
GStreamer Plugin: Embedded video playback halted; module source reported: Could not read from resource.
Error: no frame data.

如果我指定视频文件的路径作为参数，它可以很好地播放视频。

如果有任何帮助，我将不胜感激。提前感谢！

Answer 1

Opencv 2.4.6上有一个错误，请查看此处

此外，请尝试以下操作：cv:：VideoCapture cap=cv:：视频捕获（0）；

希望它能有所帮助！

Answer 2

您可以尝试将waitKey(20)值更改为20到80。一些计算机的工作值为20,30,40,50…