我应该更改使用另一个USB wecam，而不是笔记本电脑集成相机

Question

我发现了一个有趣的应用程序代码，你可以通过DirectShow在PictureBox1中捕获图像并将其放在另一个PictureBox2中。

我已经尝试过，它可以与我的笔记本电脑集成相机一起使用。

请有人告诉我应该更改哪些参数以使用另一个我在笔记本电脑上放入USB端口而不是集成摄像头的wecam吗？

这是整个代码，只需要对DirectShowLib.dll的引用。

谢谢。

Imports DirectShowLib
Imports System
Imports System.Diagnostics
Imports System.Drawing
Imports System.Runtime.InteropServices
Imports System.Windows.Forms
Imports System.Runtime.InteropServices.ComTypes

Public Class Form1

Dim D As Integer = Convert.ToInt32("0X8000", 16)
Public WM_GRAPHNOTIFY As Integer = D + 1

Dim VideoWindow As IVideoWindow = Nothing
Dim MediaControl As IMediaControl = Nothing
Dim MediaEventEx As IMediaEventEx = Nothing
Dim GraphBuilder As IGraphBuilder = Nothing
Dim CaptureGraphBuilder As ICaptureGraphBuilder2 = Nothing

Enum PlayState
    Stopped
    Paused
    Running
    Init
End Enum
Dim CurrentState As PlayState = PlayState.Stopped

Dim rot As DsROTEntry = Nothing

Private Sub Form1_FormClosing(ByVal sender As Object, ByVal e As System.Windows.Forms.FormClosingEventArgs)
    On Error Resume Next
    closeinter()
End Sub

Private Sub Form1_FormClosed(sender As Object, e As System.Windows.Forms.FormClosedEventArgs) Handles Me.FormClosed
    On Error Resume Next
End Sub

Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
    CaptureVideo()
    PictureBox1.Visible = True
End Sub

Private Sub CaptureVideo()
    Dim hr As Integer = 0
    Dim sourceFilter As IBaseFilter = Nothing
    Try
        GetInter()

        hr = CaptureGraphBuilder.SetFiltergraph(GraphBuilder) 'Specifies filter graph "graphbuilder" for the capture graph builder "captureGraphBuilder" to use.

        sourceFilter = FindCaptureDevice()

        hr = GraphBuilder.AddFilter(sourceFilter, "Video Capture")

        hr = CaptureGraphBuilder.RenderStream(PinCategory.Preview, MediaType.Video, sourceFilter, Nothing, Nothing)

        Marshal.ReleaseComObject(sourceFilter)

        SetupVideoWindow()

        rot = New DsROTEntry(GraphBuilder)

        hr = MediaControl.Run()

        CurrentState = PlayState.Running

    Catch ex As Exception
        MessageBox.Show("An unrecoverable error has occurred.With error : " & ex.ToString)
    End Try
End Sub

Private Sub GetInter()
    Dim hr As Integer = 0
    GraphBuilder = CType(New FilterGraph, IGraphBuilder)
    CaptureGraphBuilder = CType(New CaptureGraphBuilder2, ICaptureGraphBuilder2)
    MediaControl = CType(GraphBuilder, IMediaControl)
    VideoWindow = CType(GraphBuilder, IVideoWindow)
    MediaEventEx = CType(GraphBuilder, IMediaEventEx)
    hr = MediaEventEx.SetNotifyWindow(Me.Handle, WM_GRAPHNOTIFY, IntPtr.Zero) 'This method designates a window as the recipient of messages generated by or sent to the current DirectShow object
End Sub

Public Function FindCaptureDevice() As IBaseFilter

    Dim hr As Integer = 0
    Dim classEnum As IEnumMoniker = Nothing
    Dim moniker As IMoniker() = New IMoniker(0) {}
    Dim source As Object = Nothing
    Dim devEnum As ICreateDevEnum = CType(New CreateDevEnum, ICreateDevEnum)
    hr = devEnum.CreateClassEnumerator(FilterCategory.VideoInputDevice, classEnum, 0)

    Marshal.ReleaseComObject(devEnum)
    If classEnum Is Nothing Then
        Throw New ApplicationException("No video capture device was detected.\r\n\r\n" & _
                       "This sample requires a video capture device, such as a USB WebCam,\r\n" & _
                       "to be installed and working properly.  The sample will now close.")
    End If
    If classEnum.Next(moniker.Length, moniker, IntPtr.Zero) = 0 Then
        Dim iid As Guid = GetType(IBaseFilter).GUID
        moniker(0).BindToObject(Nothing, Nothing, iid, source)
    Else
        Throw New ApplicationException("Unable to access video capture device!")
    End If
    Marshal.ReleaseComObject(moniker(0))
    Marshal.ReleaseComObject(classEnum)
    Return CType(source, IBaseFilter)
End Function

Public Sub SetupVideoWindow()
    Dim hr As Integer = 0
    'set the video window to be a child of the main window
    'putowner : Sets the owning parent window for the video playback window. 
    hr = VideoWindow.put_Owner(PictureBox1.Handle) 'Me.Handle)
    PictureBox1.Visible = False

    hr = VideoWindow.put_WindowStyle(WindowStyle.Child Or WindowStyle.ClipChildren)

    'Use helper function to position video window in client rect of main application window
    ResizeVideoWindow()

    'Make the video window visible, now that it is properly positioned
    'put_visible : This method changes the visibility of the video window. 
    hr = VideoWindow.put_Visible(OABool.True)

End Sub

Public Sub ResizeVideoWindow()
    'Resize the video preview window to match owner window size
    'left , top , width , height
    If Not (VideoWindow Is Nothing) Then 'if the videopreview is not nothing
        VideoWindow.SetWindowPosition(0, 0, Me.Width, Me.ClientSize.Height)
    End If
End Sub

Public Sub closeinter()
    On Error Resume Next
    '//stop previewing data
    If Not (Me.MediaControl Is Nothing) Then
        Me.MediaControl.StopWhenReady()
    End If

    Me.CurrentState = PlayState.Stopped

    '//stop recieving events
    If Not (Me.MediaEventEx Is Nothing) Then
        Me.MediaEventEx.SetNotifyWindow(IntPtr.Zero, WM_GRAPHNOTIFY, IntPtr.Zero)
    End If

    '// Relinquish ownership (IMPORTANT!) of the video window.
    '// Failing to call put_Owner can lead to assert failures within
    '// the video renderer, as it still assumes that it has a valid
    '// parent window.
    If Not (Me.VideoWindow Is Nothing) Then
        Me.VideoWindow.put_Visible(OABool.False)
        Me.VideoWindow.put_Owner(IntPtr.Zero)
    End If

    ' // Remove filter graph from the running object table
    If Not (rot Is Nothing) Then
        rot.Dispose()
        rot = Nothing
    End If

    '// Release DirectShow interfaces
    Marshal.ReleaseComObject(Me.MediaControl) : Me.MediaControl = Nothing
    Marshal.ReleaseComObject(Me.MediaEventEx) : Me.MediaEventEx = Nothing
    Marshal.ReleaseComObject(Me.VideoWindow) : Me.VideoWindow = Nothing
    Marshal.ReleaseComObject(Me.GraphBuilder) : Me.GraphBuilder = Nothing
    Marshal.ReleaseComObject(Me.CaptureGraphBuilder) : Me.CaptureGraphBuilder = Nothing

End Sub


Public Sub GrabImage()

    ' Get image from clipboard and convert it to a bitmap

    MediaControl.Pause()

    Try
        MediaControl.Pause()



        Dim bmp As New Bitmap(PictureBox1.Width, PictureBox1.Height)
        Using g As Graphics = Graphics.FromImage(bmp)
            Dim pt As Point = PictureBox1.PointToScreen(New Point(0, 0))
            g.CopyFromScreen(pt.X, pt.Y, 0, 0, bmp.Size)
        End Using
        PictureBox2.Image = bmp

        MediaControl.Run()
    Catch
    End Try
End Sub


Private Sub btnRun_Click_1(sender As System.Object, e As System.EventArgs) Handles btnRun.Click
    MediaControl.Run()
End Sub

Private Sub btnGrab_Click_1(sender As System.Object, e As System.EventArgs) Handles btnGrab.Click
    GrabImage()
End Sub

Private Sub btnClose_Click(sender As System.Object, e As System.EventArgs) Handles btnClose.Click
    End
    Me.Close()
End Sub

结束班