[VB6] Catturare screenshot di Windows Media Player

[gprox]

Ciao a tutti sotto xp ho utilizzato il seguente codice per catturare uno screenshot dal controllo wmp, non capisco perchè sotto il 7 non funziona, non ottengo niente se no una schermata nera, provando a fare stamprsist con da tastiera funziona, però a me serve solo quel rettangolo e no tutto il monitor, vi riporto il codice che in fase di compilazione non da errore xò poi una volta eseguito da un risultato diverso in base all'OS

MODULO

Public Type GUID
   data1 As Long
   data2 As Integer
   data3 As Integer
   data4(7) As Byte
End Type

Public Type PicBmp
   Size As Long
   Type As Long
   hBmp As Long
   hpal As Long
   Reserved As Long
End Type

Public Type RECT
    Left As Long
    Top As Long
    Right As Long
    Bottom As Long
End Type


'''''''''
'Windows API Declarations
'''''''''
Public Declare Function GetWindowRect Lib "user32" (ByVal hWnd As Long, lpRect As RECT) As Long
Public Declare Function GetWindowDC Lib "user32" (ByVal hWnd As Long) As Long
Public Declare Function CreateCompatibleDC Lib "gdi32" (ByVal hDC As Long) As Long
Public Declare Function CreateCompatibleBitmap Lib "gdi32" (ByVal hDC As Long, ByVal nWidth As Long, ByVal nHeight As Long) As Long
Public Declare Function DeleteDC Lib "gdi32" (ByVal hDC As Long) As Long
Public Declare Function SelectObject Lib "gdi32" (ByVal hDC As Long, ByVal hObject As Long) As Long
Public Declare Function BitBlt Lib "gdi32" (ByVal hDCDest As Long, ByVal XDest As Long, ByVal YDest As Long, ByVal nWidth As Long, ByVal nHeight As Long, ByVal hDCSrc As Long, ByVal XSrc As Long, ByVal YSrc As Long, ByVal dwRop As Long) As Long
Public Declare Function ReleaseDC Lib "user32" (ByVal hWnd As Long, ByVal hDC As Long) As Long
Public Declare Function OleCreatePictureIndirect Lib "olepro32" (PicDesc As PicBmp, RefIID As GUID, ByVal fPictureOwnsHandle As Long, IPIC As IPicture) As Long
Public Declare Function BringWindowToTop Lib "user32" (ByVal hWnd As Long) As Long

Public Function GetScreenshot(WndHandle As Long, SavePath As String, Optional BringFront As Integer = 1) As Long
'
' Function to create screeenshot of specified window and store at specified path
'
    On Error GoTo ErrorHandler

    Dim hDCSrc As Long
    Dim hDCMemory As Long
    Dim hBmp As Long
    Dim hBmpPrev As Long
    Dim WidthSrc As Long
    Dim HeightSrc As Long
    Dim Pic As PicBmp
    Dim IPIC As IPicture
    Dim IID_IDispatch As GUID
    Dim rc As RECT
    Dim pictr As PictureBox
    
    
    'Bring window on top of all windows if specified
    If BringFront = 1 Then BringWindowToTop WndHandle
    
    'Get Window Size
    GetWindowRect WndHandle, rc
    WidthSrc = rc.Right - rc.Left
    HeightSrc = rc.Bottom - rc.Top
    
    'Get Window  device context
    hDCSrc = GetWindowDC(WndHandle)
    
    'create a memory device context
    hDCMemory = CreateCompatibleDC(hDCSrc)
    
    'create a bitmap compatible with window hdc
    hBmp = CreateCompatibleBitmap(hDCSrc, WidthSrc, HeightSrc)
    
    'copy newly created bitmap into memory device context
    hBmpPrev = SelectObject(hDCMemory, hBmp)
    
    
    'copy window window hdc to memory hdc
    Call BitBlt(hDCMemory, 0, 0, WidthSrc, HeightSrc, _
                hDCSrc, 0, 0, vbSrcCopy)
      
    'Get Bmp from memory Dc
    hBmp = SelectObject(hDCMemory, hBmpPrev)
    
    'release the created objects and free memory
    Call DeleteDC(hDCMemory)
    Call ReleaseDC(WndHandle, hDCSrc)
    
    'fill in OLE IDispatch Interface ID
    With IID_IDispatch
       .data1 = &H20400
       .data4(0) = &HC0
       .data4(7) = &H46
     End With
    
    'fill Pic with necessary parts
    With Pic
       .Size = Len(Pic)         'Length of structure
       .Type = vbPicTypeBitmap  'Type of Picture (bitmap)
       .hBmp = hBmp             'Handle to bitmap
       .hpal = 0&               'Handle to palette (may be null)
     End With
    
    'create OLE Picture object
    Call OleCreatePictureIndirect(Pic, IID_IDispatch, 1, IPIC)
    
    'return the new Picture object
    SavePicture IPIC, SavePath
    GetScreenshot = 1
    Exit Function
    
ErrorHandler:
    GetScreenshot = 0
End Function

[alka]

Il problema è legato probabilmente alla tecnica overlay utilizzata da Windows Media Player per mostrare i filmati sul video: il disegno non avviene usando le normali funzioni GDI di Windows, così come avviene per le applicazioni tradizionali, ma si stabilisce un "rapporto particolare" tra il lettore multimediale e la scheda grafica, volto a velocizzare al massimo la riproduzione del filmato usando un canale scorciatoia e "scrivendo" direttamente il filmato a video.

[gprox]

E non esiste un modo per aggirare questa cosa ? E quindi di catturare il video ?

[alka]

Originariamente inviato da gprox
E non esiste un modo per aggirare questa cosa ? E quindi di catturare il video ?

Onestamente non la conosco. Prova a fare una ricerca in merito.

[gprox]

ieri ho passato mezzo pomeriggio a cercare su google: vb6 win 7 catturare wmp e mile altre parole ma niente