在 Delphi 下使用 DirectSound (11): 测试压缩效果器 IDirectSoundFXCompressor8

{相关结构:}

TDSFXCompressor = = packed record

  fGain: Single;      // -60 .. 60   : 0  (dB)

  fAttack: Single;    //0.01 .. 500  : 10 (ms)

  fRelease: Single;   //  50 .. 3000 : 200(ms)

  fThreshold: Single; // -60 .. 0    : -20(dB)

  fRatio: Single;     //   1 .. 100  : 3  (%)

  fPredelay: Single;  //   0 .. 4    : 4  (ms)

end;



//该结构相关常量:

DSFXCOMPRESSOR_GAIN_MIN      = -60.0;

DSFXCOMPRESSOR_GAIN_MAX      = 60.0;



DSFXCOMPRESSOR_ATTACK_MIN    = 0.01;

DSFXCOMPRESSOR_ATTACK_MAX    = 500.0;



DSFXCOMPRESSOR_RELEASE_MIN   = 50.0;

DSFXCOMPRESSOR_RELEASE_MAX   = 3000.0;



DSFXCOMPRESSOR_THRESHOLD_MIN = -60.0;

DSFXCOMPRESSOR_THRESHOLD_MAX = 0.0;



DSFXCOMPRESSOR_RATIO_MIN     = 1.0;

DSFXCOMPRESSOR_RATIO_MAX     = 100.0;



DSFXCOMPRESSOR_PREDELAY_MIN  = 0.0;

DSFXCOMPRESSOR_PREDELAY_MAX  = 4.0;

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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, ExtCtrls;



type

  TForm1 = class(TForm)

    Button1: TButton;

    Button2: TButton;

    LabeledEdit1: TLabeledEdit;

    LabeledEdit2: TLabeledEdit;

    LabeledEdit3: TLabeledEdit;

    LabeledEdit4: TLabeledEdit;

    LabeledEdit5: TLabeledEdit;

    LabeledEdit6: 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;

  fxCompressor: IDirectSoundFXCompressor8; //IDirectSoundFXCompressor8 效果器



procedure TForm1.FormCreate(Sender: TObject);

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';



  LabeledEdit1.EditLabel.Caption := 'fGain: -60 - 60';

  LabeledEdit1.Text := '0.0';

  LabeledEdit1.Tag := 1;



  LabeledEdit2.EditLabel.Caption := 'fAttack: 0.01 - 500';

  LabeledEdit2.Text := '10.0';

  LabeledEdit2.Tag := 2;



  LabeledEdit3.EditLabel.Caption := 'fRelease: 50 - 3000';

  LabeledEdit3.Text := '200.0';

  LabeledEdit3.Tag := 3;



  LabeledEdit4.EditLabel.Caption := 'fThreshold: -60 - 0';

  LabeledEdit4.Text := '-20.0';

  LabeledEdit4.Tag := 4;



  LabeledEdit5.EditLabel.Caption := 'fRatio: 1 - 100';

  LabeledEdit5.Text := '3.0';

  LabeledEdit5.Tag := 5;



  LabeledEdit6.EditLabel.Caption := 'fPredelay: 0 - 4';

  LabeledEdit6.Text := '4.0';

  LabeledEdit6.Tag := 6;



  LabeledEdit2.OnChange := LabeledEdit1.OnChange;

  LabeledEdit3.OnChange := LabeledEdit1.OnChange;

  LabeledEdit4.OnChange := LabeledEdit1.OnChange;

  LabeledEdit5.OnChange := LabeledEdit1.OnChange;

  LabeledEdit6.OnChange := LabeledEdit1.OnChange;

end;



procedure TForm1.Button1Click(Sender: TObject);

var

  buf: IDirectSoundBuffer;

  bufDesc: TDSBufferDesc;

  rEffect: TDSEffectDesc;

  wav: TReadWave;

  p1: Pointer;

  n1: DWORD;

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_COMPRESSOR;

  buf8.SetFX(1, @rEffect, nil);

  buf8.GetObjectInPath(GUID_DSFX_STANDARD_COMPRESSOR, 0, IID_IDirectSoundFXCompressor8, fxCompressor);

  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

  rCompressor: TDSFXCompressor;

  f: Single;

  obj: TLabeledEdit;

begin

  obj := Sender as TLabeledEdit;

  if obj.Text = '-' then Exit;



  f := StrToFloatDef(obj.Text, MaxInt);

  case obj.Tag of

    1: if (f < -60)  or (f > 60)   then obj.Text := '0.0';

    2: if (f < 0.01) or (f > 500)  then obj.Text := '10.0';

    3: if (f < 50) then Exit else if (f > 3000) then obj.Text := '200.0';

    4: if (f < -60)  or (f > 0)    then obj.Text := '-20.0';

    5: if (f < 1)    or (f > 100)  then obj.Text := '3.0';

    6: if (f < 0)    or (f > 4)    then obj.Text := '4.0';

  end;



  if buf8 = nil then Exit;

  rCompressor.fGain      := StrToFloat(LabeledEdit1.Text);

  rCompressor.fAttack    := StrToFloat(LabeledEdit2.Text);

  rCompressor.fRelease   := StrToFloat(LabeledEdit3.Text);

  rCompressor.fThreshold := StrToFloat(LabeledEdit4.Text);

  rCompressor.fRatio     := StrToFloat(LabeledEdit5.Text);

  rCompressor.fPredelay  := StrToFloat(LabeledEdit6.Text);

  fxCompressor.SetAllParameters(rCompressor);

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 = 307

  ClientWidth = 306

  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 = 75

    Width = 75

    Height = 25

    Caption = 'Button2'

    TabOrder = 1

    OnClick = Button2Click

  end

  object LabeledEdit1: TLabeledEdit

    Left = 144

    Top = 30

    Width = 121

    Height = 21

    EditLabel.Width = 61

    EditLabel.Height = 13

    EditLabel.Caption = 'LabeledEdit1'

    TabOrder = 2

    OnChange = LabeledEdit1Change

  end

  object LabeledEdit2: TLabeledEdit

    Left = 144

    Top = 77

    Width = 121

    Height = 21

    EditLabel.Width = 61

    EditLabel.Height = 13

    EditLabel.Caption = 'LabeledEdit2'

    TabOrder = 3

  end

  object LabeledEdit3: TLabeledEdit

    Left = 144

    Top = 125

    Width = 121

    Height = 21

    EditLabel.Width = 61

    EditLabel.Height = 13

    EditLabel.Caption = 'LabeledEdit3'

    TabOrder = 4

  end

  object LabeledEdit4: TLabeledEdit

    Left = 144

    Top = 173

    Width = 121

    Height = 21

    EditLabel.Width = 61

    EditLabel.Height = 13

    EditLabel.Caption = 'LabeledEdit4'

    TabOrder = 5

  end

  object LabeledEdit5: TLabeledEdit

    Left = 144

    Top = 221

    Width = 121

    Height = 21

    EditLabel.Width = 61

    EditLabel.Height = 13

    EditLabel.Caption = 'LabeledEdit5'

    TabOrder = 6

  end

  object LabeledEdit6: TLabeledEdit

    Left = 144

    Top = 269

    Width = 121

    Height = 21

    EditLabel.Width = 61

    EditLabel.Height = 13

    EditLabel.Caption = 'LabeledEdit6'

    TabOrder = 7

  end

end

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运行效果图:

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