OpenCV VideoCapture 根本无法从我的网络摄像头读取数据答案

【问题标题】：OpenCV VideoCapture can't read from my webcam at allOpenCV VideoCapture 根本无法从我的网络摄像头读取数据
【发布时间】：2013-07-11 02:32:15
【问题描述】：

我在 Ubuntu 13.04（在 Acer C7 Chromebook 上）上使用 OpenCV 2.4.6，并且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可以与 OpenCV 一起使用。它适用于 Cheese 和 Skype，所以我知道网络摄像头本身不是问题。

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，它可以正常播放视频。

如果有任何帮助，我将不胜感激。提前致谢！

【问题讨论】：

标签： c++ opencv ubuntu webcam video-capture

【解决方案1】：

Opencv 2.4.6 有bug请看here

此外，试试这个： cv::VideoCapture cap = cv::VideoCapture(0);

希望对您有所帮助！

【讨论】：

哇。在过去的一周里，这让我很难过，所以我很高兴他们今天修复了它。非常感谢！
我刚刚删除了 2.4.6 并安装了 2.4.6.1，我的代码运行良好！
很高兴看到您一切顺利。

【解决方案2】：

您可以尝试将 waitKey(20) 的值更改为 20 到 80。某些计算机的工作值是 20、30、40、50....

【讨论】：