Author: Tomas Rutkauskas

How to get and set the volume on a wave device

Answer:

Here are a couple of functions for getting/ setting the volume on the default wave 
device:


1   uses
2     mmsystem;
3   
4   function GetWaveVolume: DWord;
5   var
6     Woc: TWAVEOUTCAPS;
7     Volume: DWord;
8   begin
9     if WaveOutGetDevCaps(WAVE_MAPPER, @Woc, sizeof(Woc)) = MMSYSERR_NOERROR then
10      if Woc.dwSupport and WAVECAPS_VOLUME = WAVECAPS_VOLUME then
11      begin
12        WaveOutGetVolume(WAVE_MAPPER, @Volume);
13        Result := Volume;
14      end;
15  end;
16  
17  procedure SetWaveVolume(const AVolume: DWord);
18  var
19    Woc: TWAVEOUTCAPS;
20  begin
21    if WaveOutGetDevCaps(WAVE_MAPPER, @Woc, sizeof(Woc)) = MMSYSERR_NOERROR then
22      if Woc.dwSupport and WAVECAPS_VOLUME = WAVECAPS_VOLUME then
23        WaveOutSetVolume(WAVE_MAPPER, AVolume);
24  end;
25  
26  
27  //Here's how they might be used:
28  
29  
30  procedure TForm1.Button2Click(Sender: TObject);
31  var
32    LeftVolume: Word;
33    RightVolume: Word;
34  begin
35    LeftVolume := StrToInt(Edit1.Text);
36    RightVolume := StrToInt(Edit2.Text);
37    SetWaveVolume(MakeLong(LeftVolume, RightVolume));
38  end;
39  
40  procedure TForm1.Button3Click(Sender: TObject);
41  begin
42    Caption := IntToStr(GetWaveVolume);
43  end;