Message-ID: <3BCCAE47.242F9972@borland.newsgroups>
Date: Wed, 17 Oct 2001 08:01:43 +1000
From: Charles Hacker <reply.to@borland.newsgroups>
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Subject: Re: Volume control
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Marco Branco wrote:
> 
> 1 - How could i control both left and right volume independently?
> 2 - How could i control the main volume buton to both sides (right and left

uses mmsystem;

function GetWaveVolume: DWord;
var
  Woc : TWAVEOUTCAPS;
  Volume : DWord;
begin
  if WaveOutGetDevCaps(WAVE_MAPPER, @Woc, sizeof(Woc)) =
MMSYSERR_NOERROR then
    if Woc.dwSupport and WAVECAPS_VOLUME = WAVECAPS_VOLUME then
    begin
      WaveOutGetVolume(WAVE_MAPPER, @Volume);
      Result := Volume;
    end;
end;

procedure SetWaveVolume(const AVolume: DWord);
var
  Woc : TWAVEOUTCAPS;
begin
  if WaveOutGetDevCaps(WAVE_MAPPER, @Woc, sizeof(Woc)) =
MMSYSERR_NOERROR then
    if Woc.dwSupport and WAVECAPS_VOLUME = WAVECAPS_VOLUME then
      WaveOutSetVolume(WAVE_MAPPER, AVolume);
end;

Here's how they might be used:

procedure TForm1.Button2Click(Sender: TObject);
var
  LeftVolume: Word;
  RightVolume: Word;
begin
  LeftVolume := StrToInt(Edit1.Text);
  RightVolume := StrToInt(Edit2.Text);
  SetWaveVolume(MakeLong(LeftVolume, RightVolume));
end;

procedure TForm1.Button3Click(Sender: TObject);
begin
  Caption := IntToStr(GetWaveVolume);
end;

-- 
Charles Hacker
Lecturer in Electronics and Computing
School of Engineering
Griffith University - Gold Coast
Australia