Delphi中用多媒体库Bass.dll播放mp3 [5]

本例效果图:

代码文件:

unit Unit1;
interface
uses
　 Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
　 Dialogs, StdCtrls, ExtCtrls, ComCtrls;
type
　 TForm1 = class(TForm)
　　 OpenDialog1: TOpenDialog;
　　 Button1: TButton;
　　 Button2: TButton;
　　 Button3: TButton;
　　 TrackBar1: TTrackBar;
　　 TrackBar2: TTrackBar;
　　 Label1: TLabel;
　　 Label2: TLabel;
　　 procedure FormCreate(Sender: TObject);
　　 procedure Button1Click(Sender: TObject);
　　 procedure Button2Click(Sender: TObject);
　　 procedure Button3Click(Sender: TObject);
　　 procedure TrackBar1Change(Sender: TObject);
　　 procedure TrackBar2Change(Sender: TObject);
　　 procedure FormDestroy(Sender: TObject);
　 end;
var
　 Form1: TForm1;
implementation
{$R *.dfm}
uses Bass;
var
　 hs: HSTREAM;　{流句柄}
procedure TForm1.FormCreate(Sender: TObject);
begin
　 TrackBar1.ShowSelRange := False;
　 TrackBar1.Min := 0;
　 TrackBar1.Max := 40;
　 TrackBar1.Position := TrackBar1.Max;
　 TrackBar2.ShowSelRange := False;
　 TrackBar2.Min := -20;
　 TrackBar2.Max := 20;
　 TrackBar2.Position := 0;
　 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;
begin
　 BASS_StreamFree(hs);
　 OpenDialog1.Filter := 'Mp3 文件(*.mp3)|*.mp3|Wav 文件(*.wav)|*wav';
　 if OpenDialog1.Execute then
　　 Mp3Path := AnsiString(OpenDialog1.FileName);
　 hs := BASS_StreamCreateFile(False, PAnsiChar(Mp3Path), 0, 0, 0);
　 if hs < BASS_ERROR_ENDED then
　　 Text := '打开失败'
　 else begin
　　 TrackBar1Change(nil);
　　 TrackBar2Change(nil);
　　 Text := string(Mp3Path);
　 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;
{设置和获取音量}
procedure TForm1.TrackBar1Change(Sender: TObject);
var
　 vol: Single;
begin
　 BASS_ChannelSetAttribute(hs, BASS_ATTRIB_VOL, TrackBar1.Position / TrackBar1.Max);
　 BASS_ChannelGetAttribute(hs, BASS_ATTRIB_VOL, vol);
　 Label1.Caption := Format('当前音量值: %f', [vol]);
end;
{设置和获取相位}
procedure TForm1.TrackBar2Change(Sender: TObject);
var
　 pan: Single;
begin
　 BASS_ChannelSetAttribute(hs, BASS_ATTRIB_PAN, TrackBar2.Position / TrackBar2.Max);
　 BASS_ChannelGetAttribute(hs, BASS_ATTRIB_PAN, pan);
　 Label2.Caption := Format('当前相位值: %f', [pan]);
end;
procedure TForm1.FormDestroy(Sender: TObject);
begin
　 BASS_Free;
end;
end.