获取MP3 信息
以前做的一个MP3播放器,怎么读取mp3文件的信息,曾经走了不少弯路,看到网上标准的取信息的方法,于是重新整理后,收藏了。
public struct Mp3Info |
{ |
public string identify;//TAG,三个字节 |
public string Title;//歌曲名,30个字节 |
public string Artist;//歌手名,30个字节 |
public string Album;//所属唱片,30个字节 |
public string Year;//年,4个字符 |
public string Comment;//注释,28个字节 |
public char reserved1;//保留位,一个字节 |
public char reserved2;//保留位,一个字节 |
public char reserved3;//保留位,一个字节 |
} |
/// <summary> |
/// mp3类 |
/// </summary> |
public class clsMP3 |
{ |
public void fLogSave(Page _sender, Hashtable _htUser) |
{ |
} |
//所以,我们只要把MP3文件的最后128个字节分段读出来并保存到该结构里就可以了。函数定义如下: |
private byte[] getLast128(string FileName) |
{ |
FileStream fs = new FileStream(FileName, FileMode.Open, FileAccess.Read); |
Stream stream = fs; |
stream.Seek(-128, SeekOrigin.End); |
const int seekPos = 128; |
int rl = 0; |
byte[] Info = new byte[seekPos]; |
rl = stream.Read(Info, 0, seekPos); |
fs.Close(); |
stream.Close(); |
return Info; |
} |
//再对上面返回的字节数组分段取出,并保存到Mp3Info结构中返回: |
private Mp3Info getMp3Info(byte[] Info) |
{ |
Mp3Info mp3Info = new Mp3Info(); |
string str = null; |
int i; |
int position = 0;//循环的起始值 |
int currentIndex = 0;//Info的当前索引值 |
//获取TAG标识(数组前3个) |
for (i = currentIndex; i < currentIndex + 3; i++) |
{ |
str = str + (char)Info[i]; |
position++; |
} |
currentIndex = position; |
mp3Info.identify = str; |
//获取歌名(数组3-32) |
str = null; |
byte[] bytTitle = new byte[30];//将歌名部分读到一个单独的数组中 |
int j = 0; |
for (i = currentIndex; i < currentIndex + 30; i++) |
{ |
bytTitle[j] = Info[i]; |
position++; |
j++; |
} |
currentIndex = position; |
mp3Info.Title = this.byteToString(bytTitle); |
//获取歌手名(数组33-62) |
str = null; |
j = 0; |
byte[] bytArtist = new byte[30];//将歌手名部分读到一个单独的数组中 |
for (i = currentIndex; i < currentIndex + 30; i++) |
{ |
bytArtist[j] = Info[i]; |
position++; |
j++; |
} |
currentIndex = position; |
mp3Info.Artist = this.byteToString(bytArtist); |
//获取唱片名(数组63-92) |
str = null; |
j = 0; |
byte[] bytAlbum = new byte[30];//将唱片名部分读到一个单独的数组中 |
for (i = currentIndex; i < currentIndex + 30; i++) |
{ |
bytAlbum[j] = Info[i]; |
position++; |
j++; |
} |
currentIndex = position; |
mp3Info.Album = this.byteToString(bytAlbum); |
//获取年 (数组93-96) |
str = null; |
j = 0; |
byte[] bytYear = new byte[4];//将年部分读到一个单独的数组中 |
for (i = currentIndex; i < currentIndex + 4; i++) |
{ |
bytYear[j] = Info[i]; |
position++; |
j++; |
} |
currentIndex = position; |
mp3Info.Year = this.byteToString(bytYear); |
//获取注释(数组97-124) |
str = null; |
j = 0; |
byte[] bytComment = new byte[28];//将注释部分读到一个单独的数组中 |
for (i = currentIndex; i < currentIndex + 25; i++) |
{ |
bytComment[j] = Info[i]; |
position++; |
j++; |
} |
currentIndex = position; |
mp3Info.Comment = this.byteToString(bytComment); |
//以下获取保留位(数组125-127) |
mp3Info.reserved1 = (char)Info[++position]; |
mp3Info.reserved2 = (char)Info[++position]; |
mp3Info.reserved3 = (char)Info[++position]; |
return mp3Info; |
} |
//上面程序用到下面的方法: |
/// <summary> |
/// 将字节数组转换成字符串 |
/// </summary> |
/// <param name = "b">字节数组</param> |
/// <returns>返回转换后的字符串</returns> |
private string byteToString(byte[] b) |
{ |
Encoding enc = Encoding.GetEncoding("GB2312"); |
string str = enc.GetString(b); |
str = str.Substring(0, str.IndexOf('\0') >= 0 ? str.IndexOf('\0') : str.Length);//去掉无用字符 |
return str; |
} |
} |
获取mp3文件的信息可以这样做,不由得想试一下其它的文件,结果发现都不行。要么取得的是文件数据,要么是乱码,或者为空,看来每个文件都有不同的属性获取方法的。
除此之外,发现竟然没有办法获取到MP3的长度信息,以前是依靠每次添加歌曲播放时提取的,真的非如此不可吗?大概是我的经验太少了吧,被这样的问题难住了这么久。