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;

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测试代码:

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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.

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窗体设计:

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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

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运行效果图:

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