● [fr]change volume (of WAV files)in delphi - 荔园在线 | 深圳大学学生论坛,荔园晨风BBS,深大在线网站

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发信人: oopilix (优雅的), 信区: Visual
标  题: [fr]change volume (of WAV files)in delphi
发信站: 荔园晨风BBS站 (Sun Jun  1 23:01:55 2003), 站内信件

1:\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\

procedure SetVolume(X : Word);
var
  iErr : Integer;
  i : integer;
  a : TAuxCaps;
begin
    for i := 0 to auxGetNumDevs do begin
        auxGetDevCaps(i,Addr(a),SizeOf(a));
        If a.wTechnology = AUXCAPS_CDAUDIO Then break;
    end;

// Sets volume equally for left and right channels.
// VOLUME := LEFT * $10000 + RIGHT * 1 (or the other way? :)

    iErr := auxSetVolume(i, (X * $10001));
    if (iErr ?? 0) then ShowMessage('No audio devices are available!');
end;

function GetVolume: Word;
var
  iErr : Integer;
  i : integer;
  a : TAuxCaps;
  vol : word;
begin
    for i := 0 to auxGetNumDevs do begin
        auxGetDevCaps(i,Addr(a),SizeOf(a));
        If a.wTechnology = AUXCAPS_CDAUDIO Then break;
    end;
    iErr:=auxGetVolume(i,addr(vol));
    GetVolume := vol;
    if (iErr??0) then ShowMessage('No audio devices are available!');
end;

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2:
1) drop a button and a trackbar onto your form.
2) Add MMSystem to your uses clause.

On you button OnClick event add this code to play your wave:=

PlaySound(PChar('C:/windows/desktop/test.wav'), hInstance, snd_ASync);

On your TrackBar OnChange event add this code:=

var
Count, i: integer;
begin
Count := waveOutGetNumDevs;
for i := 0 to Count do
begin
waveOutSetVolume(i,longint(TrackBar1.Position*4369)
*65536+longint(TrackBar1.Position*4369));
end;
**************************************
//Your entire Unit should look like this:=
**************************************

unit Unit1;

interface

uses
Windows, Messages,MMSystem, SysUtils, Classes, Graphics, Controls, Forms,
Dialogs,
ComCtrls, StdCtrls;

type
TForm1 = class(TForm)
   TrackBar1: TTrackBar;
   Button1: TButton;
   procedure TrackBar1Change(Sender: TObject);
   procedure Button1Click(Sender: TObject);
private
   { Private declarations }
public
   { Public declarations }
end;

var
Form1: TForm1;

implementation

{$R *.DFM}

procedure TForm1.TrackBar1Change(Sender: TObject);
var
Count, i: integer;
begin
Count := waveOutGetNumDevs;
for i := 0 to Count do
begin
waveOutSetVolume(i,longint(TrackBar1.Position*4369)
*65536+longint(TrackBar1.Position*4369));
end;
end;

procedure TForm1.Button1Click(Sender: TObject);
begin
PlaySound(PChar('C:/windows/desktop/test.wav'),
hInstance, snd_ASync);
end;

end.
*********************************************
//end of code

{ Adjust the path and name of your WAV file to suit.
I just tested this and it runs OK.
You could lick on both event for Btn1 & TBar1 and delete the code in your Unit
and replace it with the Unit code above}
Have fun
T.

3:
or you can download free component for that, that give you control of volume

http://homepages.borland.com/torry/mixer.htm

also look for this tip from one of expert here

How To Detect Multimedia Devices and Set their Volume
http://www.bhnet.com.br/~simonet/howtoprojs.htm

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