PureBoard

Code: Alles auswählen

;-----------------------------------------------------------------------------------------------------
;- AVI-Header-Reader 1.0
;-----------------------------------------------------------------------------------------------------
;-
;-
;- simply streams an AVI for the header and reads out it's data
;- REQUESTS a filename and an empty MainAVIHeader-structure to be filled
;- RETURN #True if all is OK, or #False if not
;-
;- see the comments and the example on how to interpretate the data
;-
;- by Froggerprogger 02.06.04
;-
#File_Temp = 0

Structure MainAVIHeader
  dwMicroSecPerFrame.l ; use this to calculate the AVIs framerate (fps = 1.000.000 / dwMicroSecPerFrame)
  dwMaxBytesPerSec.l
  dwReserved1.l
  dwFlags.l
  dwTotalFrames.l ; use this one to calculate the film's length (secs = dwTotalFrames / fps)
  dwInitialFrames.l
  dwStreams.l
  dwSuggestedBufferSize.l
  dwWidth.l
  dwHeight.l
  dwScale.l
  dwRate.l  ; a lot of AVIs let this value at 0, so use dwMicroSecPerFrame instead
  dwStart.l ; this is also set to 0 very often
  dwLength.l ; this is also set to 0 very often
EndStructure

Procedure.l GetAVIHeaderInformation(p_filename.s, *p_struct.MainAVIHeader)
  Protected tempL.l
  If ReadFile(#File_Temp, p_filename) ; open the file
   
    If ReadLong() <> 'FFIR'   ; "RIFF" ?
      ProcedureReturn #False
    EndIf
    ReadLong()                ; (not interesting) size of RIFF-chunk
    If ReadLong() <> ' IVA'   ; "AVI " ?
      ProcedureReturn #False
    EndIf
   
    Repeat
      tempL = ReadLong() ; read in the actual Long-value (4 Bytes)
      FileSeek(Loc()-3) ; go back 3 Bytes, because perhaps "avih" isn't 4-Byte-aligned
    Until Eof(#File_Temp) Or tempL = 'hiva' ; "avih" ?
   
    If tempL = 'hiva'
      FileSeek(Loc() + 7) ; go on 3 because the above and further 4 because of the not intersting chunksize
      ReadData(*p_struct, SizeOf(MainAVIHeader)) ; copy the whole header
      CloseFile(#File_Temp)
      ProcedureReturn #True
    Else
      CloseFile(#File_Temp)
      ProcedureReturn #False
    EndIf

  Else
    ProcedureReturn #False
  EndIf
EndProcedure


;- an example
myAVI_Data.MainAVIHeader

filename.s = OpenFileRequester("Choose an AVI:", "G:\Videos", "*.avi|*.avi", 0)
If filename <> ""
  If GetAVIHeaderInformation(filename, @myAVI_Data) = #False
    MessageRequester("AVI-Header-Reader:", "Error during GetAVIHeaderInformation!", #MB_ICONERROR)
  Else
    result.s = filename + ":" + Chr(13) + Chr(10)
    result + "(W/H)  " +  Str(myAVI_Data\dwWidth) + " / " + Str(myAVI_Data\dwHeight) + Chr(13) + Chr(10)
    result + StrF(1000000.0 / myAVI_Data\dwMicroSecPerFrame, 2) + " fps" + Chr(13) + Chr(10)
    result + Str(myAVI_Data\dwTotalFrames) + " frames total" + Chr(13) + Chr(10)
    MessageRequester("AVI-Header-Reader:", result, #MB_ICONINFORMATION)
  EndIf
EndIf