您所在位置：主题：[讨论]为什么摄像头，用回调函数调用视频算据总是出错
sunokboy
[专家分：10] 发布于 2010-05-02 13:11:00
[em15]
Dim lpszName As String * 100
Dim lpszVer As String * 100
Dim Caps As CAPDRIVERCAPS
capGetDriverDescriptionA 0, lpszName, 100, lpszVer, 100 '// Retrieves driver info
lwndC = capCreateCaptureWindowA(lpszName, WS_VISIBLE Or WS_CHILD, 0, 0, Picture1.ScaleWidth, Picture1.ScaleHeight, Picture1.hwnd, 0)
SetWindowText lwndC, lpszName
'// Set the video stream callback function
'capSetCallbackOnError lwndC, AddressOf MyErrorCallback
'capSetCallbackOnStatus lwndC, AddressOf MyStatusCallback
'capSetCallbackOnVideoStream lwndC, AddressOf MyVideoStreamCallback
If Not capDriverConnect(lwndC, 0) Then
MsgBox "没有找到可选用的摄像头！", vbExclamation, Me.Caption
End If
If capDriverConnect(lwndC, 0) Then
capDriverGetCaps lwndC, VarPtr(Caps), Len(Caps)
capPreviewScale lwndC, True
capPreviewRate lwndC, 34
capOverlay lwndC, True
capPreview lwndC, True
capSetCallbackOnFrame lwndC, AddressOf MyFrameCallback
capSetMCIDeviceName lwndC, VarPtr(lpszName)
SetWindowPos lwndC, HWND_BOTTOM, 0, 0, Picture1.ScaleWidth,Picture1.ScaleHeight, SWP_NOMOVE Or SWP_NOZORDER
Function MyFrameCallback(ByVal lwnd As Long, ByVal lpVHdr As Long) As Long
Debug.Print "FrameCallBack"
Dim VideoHeader As VIDEOHDR
Dim VideoData() As Byte
'//Fill VideoHeader with data at lpVHdr
RtlMoveMemory VarPtr(VideoHeader), lpVHdr, Len(VideoHeader)
'// Make room for data
ReDim VideoData(VideoHeader.dwBytesUsed)
'//Copy data into the array
RtlMoveMemory VarPtr(VideoData(0)), VideoHeader.lpData, VideoHeader.dwBytesUsed
Debug.Print VideoHeader.dwBytesUsed
Debug.Print VideoData
End Function
怎么写才把摄像头的数据取出来，后来我用了getdc(lwndC)成功取出图像，
winsock2.SendData PictureToByteArray(hDCToPicture(GetDC(lwndC), 0, 0,Picture1.ScaleWidth, Picture1.ScaleHeight), 80)可是又出现了，摄像头被遮挡住，取到的数据就变成了遮挡的部分的位图，是怎么一会事，然后用GetDCEx(lwndC, 0, DCX_CLIPSIBLINGS),失败，不知道getdcex第二个参数是什么。请高手们指点迷经。
Dim lpszName As String * 100
Dim lpszVer As String * 100
Dim Caps As CAPDRIVERCAPS
capGetDriverDescriptionA 0, lpszName, 100, lpszVer, 100 '// Retrieves driver info
lwndC = capCreateCaptureWindowA(lpszName, WS_VISIBLE Or WS_CHILD, 0, 0, Picture1.ScaleWidth, Picture1.ScaleHeight, Picture1.hwnd, 0)
SetWindowText lwndC, lpszName
'// Set the video stream callback function
'capSetCallbackOnError lwndC, AddressOf MyErrorCallback
'capSetCallbackOnStatus lwndC, AddressOf MyStatusCallback
'capSetCallbackOnVideoStream lwndC, AddressOf MyVideoStreamCallback
If Not capDriverConnect(lwndC, 0) Then
MsgBox "没有找到可选用的摄像头！", vbExclamation, Me.Caption
End If
If capDriverConnect(lwndC, 0) Then
capDriverGetCaps lwndC, VarPtr(Caps), Len(Caps)
capPreviewScale lwndC, True
capPreviewRate lwndC, 34
capOverlay lwndC, True
capPreview lwndC, True
capSetCallbackOnFrame lwndC, AddressOf MyFrameCallback
capSetMCIDeviceName lwndC, VarPtr(lpszName)
SetWindowPos lwndC, HWND_BOTTOM, 0, 0, Picture1.ScaleWidth,Picture1.ScaleHeight, SWP_NOMOVE Or SWP_NOZORDER
Function MyFrameCallback(ByVal lwnd As Long, ByVal lpVHdr As Long) As Long
Debug.Print "FrameCallBack"
Dim VideoHeader As VIDEOHDR
Dim VideoData() As Byte
'//Fill VideoHeader with data at lpVHdr
RtlMoveMemory VarPtr(VideoHeader), lpVHdr, Len(VideoHeader)
'// Make room for data
ReDim VideoData(VideoHeader.dwBytesUsed)
'//Copy data into the array
RtlMoveMemory VarPtr(VideoData(0)), VideoHeader.lpData, VideoHeader.dwBytesUsed
Debug.Print VideoHeader.dwBytesUsed
Debug.Print VideoData
End Function
怎么写才把摄像头的数据取出来，后来我用了getdc(lwndC)成功取出图像，
winsock2.SendData PictureToByteArray(hDCToPicture(GetDC(lwndC), 0, 0,Picture1.ScaleWidth, Picture1.ScaleHeight), 80)可是又出现了，摄像头被遮挡住，取到的数据就变成了遮挡的部分的位图，是怎么一会事，然后用GetDCEx(lwndC, 0, DCX_CLIPSIBLINGS),失败，不知道getdcex第二个参数是什么。请高手们指点迷经。
