用多媒体库 Bass.dll 播放 mp3 [14] - 频率均衡器

本例效果图:

---

代码文件:

---

unit Unit1;



interface



uses

  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,

  Dialogs, StdCtrls, ComCtrls, ExtCtrls;



type

  TForm1 = class(TForm)

    OpenDialog1: TOpenDialog;

    Button1: TButton;

    Button2: TButton;

    Button3: TButton;

    Panel1: TPanel;

    procedure FormCreate(Sender: TObject);

    procedure Button1Click(Sender: TObject);

    procedure Button2Click(Sender: TObject);

    procedure Button3Click(Sender: TObject);

    procedure FormDestroy(Sender: TObject);

  private

    procedure TrackChange(Sender: TObject);

  end;



var

  Form1: TForm1;



implementation



{$R *.dfm}



uses Bass;



var

  hs: HSTREAM;  {流句柄}

  parameq: BASS_DX8_PARAMEQ; {频率均衡器的参数结构}

  fx: array[0..5] of HFX;    {DX 的效果句柄}

  track: array[0..5] of TTrackBar;



procedure TForm1.FormCreate(Sender: TObject);

var

  i: Integer;

begin

  Panel1.Align := alRight;

  Panel1.BevelOuter := bvLowered;

  Panel1.BevelWidth := 2;

  Panel1.Caption := '';

  Panel1.Width := 6*24 + 2;



  for i := 0 to 5 do

  begin

    track[i] := TTrackBar.Create(Self);

    track[i].Parent := Panel1;

    track[i].Orientation := trVertical;

    track[i].Width := 23;

    track[i].Height := Panel1.Height;

    track[i].ShowSelRange := False;

    track[i].Left := i * 24 + 1;

    track[i].Max := 15;

    track[i].Min := -15;

    track[i].Position := 0;

    track[i].Tag := i;

    track[i].OnChange := Self.TrackChange;

  end;



  if HiWord(BASS_GetVersion) <> BASSVERSION then

    MessageBox(0, '"Bass.dll" 文件版本不合适! ', nil, MB_ICONERROR);



  if not BASS_Init(-1, 44100, 0, 0, nil) then ShowMessage('初始化错误');

end;



{打开}

procedure TForm1.Button1Click(Sender: TObject);

var

  Mp3Path: AnsiString;

  i: Integer;

begin

  BASS_StreamFree(hs);



  OpenDialog1.Filter := 'Mp3 文件(*.mp3)|*.mp3|Wav 文件(*.wav)|*wav';

  if OpenDialog1.Execute then

    Mp3Path := AnsiString(OpenDialog1.FileName);



  {实现混响等效果, 需要指定 BASS_SAMPLE_FX 参数}

  hs := BASS_StreamCreateFile(False, PAnsiChar(Mp3Path), 0, 0, BASS_SAMPLE_FX);



  if hs < BASS_ERROR_ENDED then

    Text := '打开失败'

  else begin

    Text := string(Mp3Path);



    {要设置多种频率范围, 就需要多个效果句柄}

    for i := 0 to 5 do

      fx[i] := BASS_ChannelSetFX(hs, BASS_FX_DX8_PARAMEQ, 1);

  end;

end;



{播放}

procedure TForm1.Button2Click(Sender: TObject);

begin

  BASS_ChannelPlay(hs, False);

end;



{暂停}

procedure TForm1.Button3Click(Sender: TObject);

begin

  BASS_ChannelPause(hs);

end;



procedure TForm1.FormDestroy(Sender: TObject);

begin

  BASS_Free;

end;



{动态建立的 TTrackBar 要调用的事件}

procedure TForm1.TrackChange(Sender: TObject);

var

  i: Integer;

begin

  i := TTrackBar(Sender).Tag;

  parameq.fBandwidth := 20; {1 - 36}

  case i of

    0: parameq.fCenter := 100;

    1: parameq.fCenter := 2000;

    2: parameq.fCenter := 4000;

    3: parameq.fCenter := 8000;

    4: parameq.fCenter := 10000;

    5: parameq.fCenter := 12000;

  end;

  parameq.fGain := - TTrackBar(Sender).Position;

  BASS_FXSetParameters(fx[i], @parameq);

end;



end.


 
   

窗体文件:

---

object Form1: TForm1

  Left = 222

  Top = 114

  Caption = 'Form1'

  ClientHeight = 132

  ClientWidth = 254

  Color = clBtnFace

  Font.Charset = DEFAULT_CHARSET

  Font.Color = clWindowText

  Font.Height = -11

  Font.Name = 'Tahoma'

  Font.Style = []

  OldCreateOrder = False

  Position = poDesigned

  OnCreate = FormCreate

  OnDestroy = FormDestroy

  PixelsPerInch = 96

  TextHeight = 13

  object Button1: TButton

    Left = 8

    Top = 17

    Width = 75

    Height = 25

    Caption = #25171#24320

    TabOrder = 0

    OnClick = Button1Click

  end

  object Button2: TButton

    Left = 8

    Top = 56

    Width = 75

    Height = 25

    Caption = #25773#25918

    TabOrder = 1

    OnClick = Button2Click

  end

  object Button3: TButton

    Left = 8

    Top = 93

    Width = 75

    Height = 25

    Caption = #26242#20572

    TabOrder = 2

    OnClick = Button3Click

  end

  object Panel1: TPanel

    Left = 92

    Top = 47

    Width = 141

    Height = 41

    Caption = 'Panel1'

    TabOrder = 3

  end

  object OpenDialog1: TOpenDialog

    Left = 80

    Top = 88

  end

end