Delphi中用多媒體庫Bass.dll播放mp3 [14] - 頻率均衡器

本例效果圖:

代碼文件:

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; {頻率均衡器的參數結構}
　 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" 文件版本不合適! ', nil, MB_ICONERROR);
　 if not BASS_Init(-1, 44100, 0, 0, nil) then ShowMessage('初始化錯誤');
end;
{打開}
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);
　 {實現混響等效果, 需要指定 BASS_SAMPLE_FX 參數}
　 hs := BASS_StreamCreateFile(False, PAnsiChar(Mp3Path), 0, 0, BASS_SAMPLE_FX);
　 if hs < BASS_ERROR_ENDED then
　　 Text := '打開失敗'
　 else begin
　　 Text := string(Mp3Path);
　　 {要設置多種頻率范圍, 就需要多個效果句柄}
　　 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;
{暫停}
procedure TForm1.Button3Click(Sender: TObject);
begin
　 BASS_ChannelPause(hs);
end;
procedure TForm1.FormDestroy(Sender: TObject);
begin
　 BASS_Free;
end;
{動態建立的 TTrackBar 要調用的事件}
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.

窗體文件:

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