Delphi realizes the control sound volume

When you do a multimedia player, it is unavoidable to control the volume and the playback of the left and right channels, the following describes a wave waveform output device Volume control method, this method is not set the main volume. First put two ttrackbar on the form, named Trackbar1,trackbar2, the attribute Max is set to 65535, if you think the scale is too dense, you can set the Frequency property value larger, and then add MMSystem in uses segment, And the following statements are written in the onchange events of TrackBar1 and TRACKBAR2:

procedure TForm1.TrackBar1Change(Sender: TObject);
var Wave:string;
begin
Wave:=$+inttohex(TrackBar1.Position,4)+inttohex(TrackBar2.Position,4);
waveoutsetvolume(0,strtoint(Wave));
end;