How to extract an audio stream of an *.avi file

Problem/Question/Abstract:

How can I extract an audio stream of an *.avi file?

Answer:

Note, you must use VfW.pas. You may find this file somewhere in the internet or simply write me an email. In addition, I was not able to test this code under Delphi 5.x or lower. Only Delphi 6.x. Please send me a piece of information, if you can test this for me. Thanks


uses VfW;

function CallBack(i: int): BOOL; pascal;
begin
  Label1.Caption := IntToStr(i) + '%';
  Application.ProcessMessages;
  Result := False;
end;

procedure TForm1.Button1Click(Sender: TObject);
var
  PFile: IAviFile;
  PAvi: IAviStream;
  plpOptions: PAviCompressOptions;
begin
  AviFileInit;
  if AviFileOpen(PFile, 'C:\test.avi', 0, nil) <> 0 then
  begin
    ShowMessage('Couldn'' t open * .avi!');
    Exit;
  end;
  if AviFileGetStream(PFile, PAvi, StreamTypeAudio, 0) <> 0 then
  begin
    ShowMessage('Couldn' t load audio stream!');
      AviFileExit;
      Exit;
  end;
  if AviSaveV('C:\test.wav', nil, @CallBack, 1, PAvi, plpOptions) <> 0 then
  begin
    ShowMessage('Couldn'' t save * .wav - file!');
    AviStreamRelease(PAvi);
    AviFileExit;
    Exit;
  end;
  AviStreamRelease(PAvi);
  AviFileExit;
end;