procedure TMainForm.N1Click(Sender: TObject);
var
s: MCI_DGV_SETAUDIO_PARMS
begin
if Nothing then
begin
//mediaplayer1 为控件NAME
mciSendCommand(MediaPlayer1.DeviceID,MCI_SETAUDIO,MCI_SET_OFF,integer(@s));
s.dwValue:=MCI_DGV_SETAUDIO_SOURCE_STEREO;
//立体声用这句
s.dwValue:=MCI_DGV_SETAUDIO_SOURCE_RIGHT;
//右声道源
s.dwValue:=MCI_DGV_SETAUDIO_SOURCE_LEFT;
//左声道源
s.dwItem:=MCI_DGV_SETAUDIO_SOURCE;
mciSendCommand(MediaPlayer1.DeviceID,MCI_SETAUDIO, MCI_DGV_SETAUDIO_VALUE or MCI_DGV_SETAUDIO_ITEM ,integer(@s));
mciSendCommand(MediaPlayer1.DeviceID,MCI_SETAUDIO, MCI_SET_ON,integer(@s));
end;
end;