在 Delphi 下使用 DirectSound (17): 频率均衡效果器 IDirectSoundFXParamEq8

{相关结构:}
TDSFXParamEq = packed record
fCenter: Single;    // 80 .. 16000 : 8000.0 (Hz)
fBandwidth: Single; //  1 .. 36    : 12.0
fGain: Single;      //-15 .. 15    : 0.0
end;

//该结构相关常量:
DSFXPARAMEQ_CENTER_MIN    = 80.0;
DSFXPARAMEQ_CENTER_MAX    = 16000.0;

DSFXPARAMEQ_BANDWIDTH_MIN = 1.0;
DSFXPARAMEQ_BANDWIDTH_MAX = 36.0;

DSFXPARAMEQ_GAIN_MIN      = -15.0;
DSFXPARAMEQ_GAIN_MAX      = 15.0;

unit Unit1;

interface

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

type
TForm1 = class(TForm)
Button1: TButton;
Button2: TButton;
LabeledEdit1: TLabeledEdit;
procedure FormCreate(Sender: TObject);
procedure FormDestroy(Sender: TObject);
procedure Button1Click(Sender: TObject);
procedure Button2Click(Sender: TObject);
procedure LabeledEdit1Change(Sender: TObject);
end;

var
Form1: TForm1;

implementation

{$R *.dfm}

uses DirectSound, ReadWave2; //ReadWave2 是前面(9)自定义的单元

var
myDSound: IDirectSound8;
buf8: IDirectSoundBuffer8;
fxParamEqs: array[0..5] of IDirectSoundFXParamEq8; //IDirectSoundFXParamEq8 效果器数组
arrTrack: array[0..5] of TTrackBar;

procedure TForm1.FormCreate(Sender: TObject);
var
i: Integer;
begin
System.ReportMemoryLeaksOnShutdown := True;
DirectSoundCreate8(nil, myDSound, nil);
myDSound.SetCooperativeLevel(Handle, DSSCL_NORMAL);

Button1.Caption := '打开并播放';
Button2.Caption := '停止播放';

for i := 5  downto 0 do
begin
arrTrack[i] := TTrackBar.Create(Self);
arrTrack[i].Parent := Self;
arrTrack[i].Orientation := trVertical;
arrTrack[i].ShowSelRange := False;
arrTrack[i].TickStyle := tsNone;
arrTrack[i].Width := 32;
arrTrack[i].Align := alRight;
arrTrack[i].Tag := i;
arrTrack[i].Min := -15;
arrTrack[i].Max := 15;
arrTrack[i].Position := 0;
arrTrack[i].OnChange := LabeledEdit1.OnChange;
end;
LabeledEdit1.EditLabel.Caption := 'fBandwidth:';
LabeledEdit1.Text := '12.0';
end;

procedure TForm1.Button1Click(Sender: TObject);
var
buf: IDirectSoundBuffer;
bufDesc: TDSBufferDesc;
rEffect: TDSEffectDesc;
wav: TReadWave;
p1: Pointer;
n1: DWORD;
i: Integer;
begin
wav := TReadWave.Create;
if not wav.OpenDialog then begin wav.Free; Exit; end;

ZeroMemory(@bufDesc, SizeOf(TDSBufferDesc));
bufDesc.dwSize := SizeOf(TDSBufferDesc);
bufDesc.dwFlags := DSBCAPS_CTRLFX;
bufDesc.dwBufferBytes := wav.Size;
bufDesc.lpwfxFormat := @wav.Format;
myDSound.CreateSoundBuffer(bufDesc, buf, nil);
buf.QueryInterface(IID_IDirectSoundBuffer8, buf8);

buf8.Lock(0, 0, @p1, @n1, nil, nil, DSBLOCK_ENTIREBUFFER);
wav.Read(p1, n1);
wav.Free;
buf8.Unlock(p1, n1, nil, 0);

ZeroMemory(@rEffect, SizeOf(TDSEffectDesc));
rEffect.dwSize := SizeOf(TDSEffectDesc);
rEffect.dwFlags := 0;
rEffect.guidDSFXClass := GUID_DSFX_STANDARD_PARAMEQ;

for i := 0 to 5 do
begin
buf8.SetFX(1, @rEffect, nil);
buf8.GetObjectInPath(GUID_DSFX_STANDARD_PARAMEQ, 0, IID_IDirectSoundFXParamEq8, fxParamEqs[i]);
end;

buf8.Play(0, 0, DSBPLAY_LOOPING);
end;

procedure TForm1.Button2Click(Sender: TObject);
begin
if Assigned(buf8) then buf8.Stop;
end;

procedure TForm1.LabeledEdit1Change(Sender: TObject);
var
rParamEqs: TDSFXParamEq;
i: Integer;
f: Single;
begin
if buf8 = nil then Exit;
if Sender.ClassNameIs('TLabeledEdit') then
begin
f := StrToFloatDef(LabeledEdit1.Text, MaxInt);
if (f < 1) or (f > 36) then LabeledEdit1.Text := '12.0';
for i := 0 to 5 do arrTrack[i].OnChange(arrTrack[i]);
end;
rParamEqs.fBandwidth := StrToFloat(LabeledEdit1.Text);

i := TTrackBar(Sender).Tag;
case i of
0: rParamEqs.fCenter := 100;
1: rParamEqs.fCenter := 2000;
2: rParamEqs.fCenter := 4000;
3: rParamEqs.fCenter := 8000;
4: rParamEqs.fCenter := 10000;
5: rParamEqs.fCenter := 12000;
end;
rParamEqs.fGain := - TTrackBar(Sender).Position;
fxParamEqs[i].SetAllParameters(rParamEqs);
end;

procedure TForm1.FormDestroy(Sender: TObject);
begin
buf8 := nil;
myDSound := nil;
end;

end.

object Form1: TForm1
Left = 0
Top = 0
Caption = 'Form1'
ClientHeight = 205
ClientWidth = 343
Color = clBtnFace
Font.Charset = DEFAULT_CHARSET
Font.Color = clWindowText
Font.Height = -11
Font.Name = 'Tahoma'
Font.Style = []
OldCreateOrder = False
OnCreate = FormCreate
OnDestroy = FormDestroy
PixelsPerInch = 96
TextHeight = 13
object Button1: TButton
Left = 32
Top = 28
Width = 75
Height = 25
Caption = 'Button1'
TabOrder = 0
OnClick = Button1Click
end
object Button2: TButton
Left = 32
Top = 67
Width = 75
Height = 25
Caption = 'Button2'
TabOrder = 1
OnClick = Button2Click
end
object LabeledEdit1: TLabeledEdit
Left = 32
Top = 144
Width = 89
Height = 21
EditLabel.Width = 61
EditLabel.Height = 13
EditLabel.Caption = 'LabeledEdit1'
TabOrder = 2
OnChange = LabeledEdit1Change
end
end