[KaktoR]

If you used BASS library, there is a example next to it.

You must create a new button

example

[_code]
var
MusicButton: TNewButton;

procedure MusicButtonClick(Sender: TObject);
  begin
    case BASS_ChannelIsActive(SoundStream) of
      BASS_ACTIVE_PLAYING:
      begin
        if BASS_Pause then
          MusicButton.Caption := 'Music ON';
      end;
      BASS_ACTIVE_PAUSED:
      begin
        if BASS_Start then
          MusicButton.Caption := 'Music OFF';
      end;
    end;
  end;

Then you habe to place the button somewhere on installer surface