Delphi with Multimedia library Bass.dll play MP3 [3]

//播放前先要用 BASS_Init 函数进行播放设备初始化
function BASS_Init(
　 device: Integer; {指定输出设备, 第一个是 1、第二个是 2; -1 表示使用当前设 备}
　 freq: DWORD;　　 {采样率, 一般是 44100}
　 flags: DWORD;　　{是 BASS_DEVICE_MONO 等常量的组合值, 是效果参数; 0 是默认值 }
　 win: HWND;　　　 {指定窗口句柄; 0 表示当前窗口}
　 clsid: PGUID　　 {指定一个 GUID, 用以初始化 DirectSound; nil 表示使用默认}
): BOOL; stdcall; external bassdll;
//当然需要从文件或内存加载文件流以后才能播放
function BASS_StreamCreateFile(
　 mem: BOOL;　　 {从文件载入这里是 False; 从内存载入这里是 True}
　 f: Pointer;　　{文件名或内存流的指针}
　 offset: QWORD; {播放起始点, 单位是 1/10 毫米; 只在参数 1: mem = False 时有效 ; 默认是 0}
　 length: QWORD; {播放终止点, 单位是 1/10 毫米; 只在参数 1: mem = False 时有效 ; 默认是 0}
　 flags: DWORD　 {BASS_SAMPLE_3D 等参数的组合; 控制播放效果、反复和解码等等}
): HSTREAM; stdcall; external bassdll;
{另外: 在调入内存流时, 参数 length 要指定为流的大小}

Form Design diagram:

Code files:

Unit Unit1;
Interface
Uses
Windows, Messages, sysutils, variants, Classes, Graphics, Controls, Forms,
Dialogs, Stdctrls;
Type
TForm1 = Class (Tform)
Opendialog1:topendialog;
Button1:tbutton;
Button2:tbutton;
Button3:tbutton;
Button4:tbutton;
Procedure Formcreate (Sender:tobject);
Procedure Button1Click (Sender:tobject);
Procedure Button2click (Sender:tobject);
Procedure Button3click (Sender:tobject);
Procedure Button4click (Sender:tobject);
Procedure Formdestroy (Sender:tobject);
End
Var
Form1:tform1;
Implementation
{$R *.DFM}
Uses Bass;
Var
Hs:hstream; {Stream Handle}
Procedure Tform1.formcreate (Sender:tobject);
Begin
If HiWord (bass_getversion) <> Bassversion Then
MessageBox (0, "Bass.dll" file version is not suitable!) ', nil, mb_iconerror);
If not Bass_init ( -1, 44100, 0, 0, nil) then
ShowMessage (' initialization error ');
End
{Open MP3 file and create play stream}
Procedure Tform1.button1click (Sender:tobject);
Var
mp3path:ansistring;
Begin
{Open File}
Opendialog1.filter: = ' Mp3 file (*.mp3) |*.mp3| Wav file (*.wav) |*wav ';
If Opendialog1.execute Then
Mp3path: = ansistring (Opendialog1.filename);
{If there is already a file open, let it be released}
Bass_streamfree (HS);
{Create play Stream}
HS: = Bass_streamcreatefile (False, Pansichar (Mp3path), 0, 0, 0);
{Whether the success is turned on, show}
If HS < bass_error_ended Then
Text: = ' open failed ' else Text: = string (Mp3path);
End
Play
Procedure Tform1.button2click (Sender:tobject);
Begin
Bass_channelplay (HS, False); {Parameter 1 is a stream handle; parameter 2 will play from the beginning every time if True}
End
Suspended
Procedure Tform1.button3click (Sender:tobject);
Begin
Bass_channelpause (HS);
End
Stop
Procedure Tform1.button4click (Sender:tobject);
Begin
Bass_channelstop (HS);
End
Release
Procedure Tform1.formdestroy (Sender:tobject);
Begin
Bass_free;
End
End.