Question

我有一个小项目，我从网络摄像头捕获图像并解码qr。

以下代码捕获图像并将其存储到本地文件但仅当它不在while循环中时。 system.threading似乎使捕获的图像只是黑色。如果我不使用它（循环），它每秒捕获太多的图像。

那么有没有办法改变aforge.video帧速率，这样我就可以每隔x秒捕捉一次图像而不用while循环？

   public partial class WebForm1 : System.Web.UI.Page
{
    public int FrameRate { get; set; }

    private FilterInfoCollection VideoCaptureDevices;
    private VideoCaptureDevice FinalVideo;

    protected void Page_Load(object sender, EventArgs e)
    {
        inputDevices.Items.Clear();

        VideoCaptureDevices = new FilterInfoCollection(FilterCategory.VideoInputDevice);
        foreach (FilterInfo VideoCaptureDevice in VideoCaptureDevices)
        {
            inputDevices.Items.Add(VideoCaptureDevice.Name);
        }
        inputDevices.SelectedIndex = 0;     
    }

    public void Start_OnClick(object sender, EventArgs e)
    {
        FinalVideo = new VideoCaptureDevice(VideoCaptureDevices[inputDevices.SelectedIndex].MonikerString);
        FinalVideo.NewFrame += new NewFrameEventHandler(FinalVideo_NewFrame);
        FinalVideo.Start();
    }
    void FinalVideo_NewFrame(object sender, NewFrameEventArgs eventArgs)
    {
        int i = 0;
        while (i < 10)
        {
            Bitmap video = (Bitmap)eventArgs.Frame.Clone();
            video.Save("C:\\Users\\Wayneio\\Desktop\\image\\test" + i + ".jpg");
            i++;
            System.Threading.Thread.Sleep(5000);
        }

    }
    public void Stop_OnClick(object sender, EventArgs e)
    {
        this.FinalVideo.Stop();
    }
}

此外，当我尝试通过asp按钮停止捕获时出现此错误：

 Object reference not set to an instance of an object on this.FinalVideo.Stop();

试了这个无济于事：（（VideoCaptureDevice）FinalVideo）。DesiredFrameRate = 10;

Answer 1

在代码开始之前

设置像这样的framreate

 FinalVideo.DesiredFrameRate = 10;
 FinalVideo.Start();

跳过保存帧的另一个选项是使用并非总是如此的函数如果你有一个全局计数器值myCounter

做一个模数计算，如下面的ix mycounter划分为10等于1

 myCounter++
 if (m(ycounter %% 10))==1) { //code to save your bitmap   }

改变帧率＆amp; System.Threading Aforge.video C＃ASP.NET

1 个答案: