Private Declare Function AVIFileOpen Lib "avifil32" Alias "AVIFileOpenA" ( _
  ppfile As Long, ByVal szFile As String, ByVal mode As Long, pclsidHandler As _
  Any) As Long
Private Declare Function AVIFileRelease Lib "avifil32" (ByVal pfile As Long) As _
Long
Private Declare Function AVIFileInfo Lib "avifil32" Alias "AVIFileInfoA" (ByVal _
pfile As Long, pfi As AVIFileInfo, ByVal lSize As Long) As Long
Private Declare Sub AVIFileInit Lib "avifil32" ()
Private Declare Sub AVIFileExit Lib "avifil32" ()
 
' AVI Info-Struktur
Private Type AVIFileInfo
  dwMaxBytesPerSec As Long
  dwFlags As Long
  dwCaps As Long
  dwStreams As Long
  dwSuggestedBufferSize As Long
  dwWidth As Long
  dwHeight As Long
  dwScale As Long
  dwRate As Long
  dwLength As Long
  dwEditCount As Long
  szFileType As String * 64
End Type

Public Function AVI_GetLength(ByVal sFile As String) As Long
  Dim hFile As Long, AviInfo As AVIFileInfo, nLength As Long
 
  AVIFileInit   ' Initialisieren
 
  ' AVI öffnen (Handle erstellen)
  If AVIFileOpen(hFile, sFile, &H20, ByVal 0&) = 0 Then
    If AVIFileInfo(hFile, AviInfo, Len(AviInfo)) = 0 Then
      nLength = AviInfo.dwLength / 25#
    End If
    AVIFileRelease hFile
  End If
 
  AVIFileExit   ' Beenden
 
  AVI_GetLength = nLength   ' Rückgabewert
End Function