我已成功使用directshow预览和录制网络摄像头中的图像，但问题是当我在平板电脑中使用该应用程序时，方向与我在PC中看到的方向不同。是否有可能旋转此预览图像？我可以在保存之前旋转从预览中获取的位图“图像”，但如果我可以在预览中显示正确的方向，那对我来说非常有帮助。
我已经阅读了一些使用igraphbuilder，渲染文件等的建议....但由于我不是一个非常有经验的VB.net开发人员，我很难理解所有这些概念。我花了很多天才找到不同的代码来使相机捕捉工作。但现在遇到了定位问题。
这个应用程序将去第三世界国家帮助协助医院工作，但我现在被困住了......如果有人能帮助我弄清楚我怎么做。我真的很感激....
这是代码的样子，如果有人可以帮助添加一些过滤器，以便我可以在90度视图中预览图像。
非常感谢!!!!
Imports DirectShowLib
Imports System
Imports System.Diagnostics
Imports System.Drawing
Imports System.Drawing.Imaging
Imports System.Runtime.InteropServices
Imports System.Windows.Forms
Imports System.Runtime.InteropServices.ComTypes
Public Class Form2
Dim MyPicturesFolder As String = Environment.GetFolderPath(Environment.SpecialFolder.MyPictures)
Dim D As Integer = &H8000
'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)
closeinterfaces()
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
GetInterfaces()
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 GetInterfaces()
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 closeinterfaces()
'//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
Private Sub btnGrab_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnGrab.Click
GrabImage()
End Sub
Public Sub GrabImage()
'
'' Get image from clipboard and convert it to a bitmap
'Try
' MediaControl.Pause()
' Clipboard.SetImage(PictureBox1.Image)
' '
' If Clipboard.ContainsImage Then
' PictureBox2.Image = Clipboard.GetImage()
' End If
'Catch
'End Try
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
PictureBox2.Visible = True
'PictureBox1.Visible = False
Catch
MsgBox("error")
End Try
End Sub
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click, btnGrab.Click
MediaControl.Run()
End Sub
Private Sub btnSave_Click(sender As System.Object, e As System.EventArgs) Handles BtnSave.Click
Dim newimage As Image = PictureBox2.Image
Dim gr As Graphics = Graphics.FromImage(newimage)
Dim myFontLabels As New Font("Arial", 40)
Dim myBrushLabels As New SolidBrush(Color.Black)
Dim FolderBrowser As New FolderBrowserDialog
If FolderBrowser.ShowDialog = Windows.Forms.DialogResult.OK Then
Me.lblPath.Text = FolderBrowser.SelectedPath & "\Amytest.bmp"
MsgBox("msg" & Me.lblPath.Text)
End If
'newimage.Save(Me.lblPath.Text, ImageFormat.Jpeg)
'MsgBox("The picture has been successfully copied and saved")
End Sub
Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
Dim newimage As Image = PictureBox2.Image
Dim gr As Graphics = Graphics.FromImage(newimage)
Dim myFontLabels As New Font("Arial", 40)
Dim myBrushLabels As New SolidBrush(Color.Black)
Dim _sourcefilename$ = Me.lblPath.Text
Dim _destinationfilename$ = "C:\test.jpg"
JpegSaveClass.SaveImage(_sourcefilename, _destinationfilename)
End Sub
答案 0 :(得分：0)
DirectShow API没有内置的旋转视频功能。假设如果需要旋转，则将外部（第三方）转换过滤器插入管道并执行转换。
多次讨论，见：