讀取MP3文件的ID3v1信息

2019-11-18 17:09:07

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來源：轉載

供稿：網友

前段時間，在局域網里面做一個小網站，其中有板塊是涉及音樂的在線播放。考慮到以后維護的方便，決定把mp3文件都按專輯分不同的目錄存放。然后使用一個程序監控存放mp3的目錄，把每個mp3文件的信息都存入數據庫中，用過 asp.net頁面將mp3文件的信息呈現給用戶。其中使用.NET來讀取mp3 文件的信息雖然不難，但也需要不少技巧，故將該過程整理與大家分享。

首先我們來看看mp3歌曲的信息所存放的位置。Mp3文件包含一個叫做ID3的標簽。其實有兩個標簽，一個叫做ID3v1，另外一個叫做ID3v2。為了講述的簡單起見，我們這里只介紹ID3v1。

ID3V1結構比較簡單，存放在MP3文件的末尾，大家可以用16進制的編輯器（例如：UltraEdit）打開一個MP3文件，注意其末尾的128個字節，數據結構定義如下：

名稱位置長度內容

Header 1-3 3 標簽頭

Title 4-33 30 標題

Artist 34-63 30 藝術家

Album 64-93 30 專輯

Year 94-97 4 出品年代

Comment 98-127 30 備注

Cenre 128 1 類型

注意：上述的標簽頭必須是”TAG”, 否則表示沒有標簽

ID3v1的各項信息是按順序依次存放的，每項信息之后并沒有任何的結束標志，如果某項信息長度小于標準長度，使用”/0”來補充。另外Genre是個例外，它用一個字節表示歌曲流派，其對應表如下(由于該內容太多，只列出前50項)：

0="Blues"

1="ClassicRock"

2="Country"

3="Dance"

4="Disco"

5="Funk"

6="Grunge"

7="H

知道了MP3歌曲信息存放的結構之后，我們就可以寫出對應的代碼。

首先定一個MP3Info類：

1 Public Class Mp3Info
2
3
4
5     Private Const TAGLEN As Integer = 128
6
7
8
9     Private _MP3Tag As String = String.Empty
10
11     Private _Artist As String = String.Empty
12
13     Private _Title As String = String.Empty
14
15     Private _Album As String = String.Empty
16
17     Private _Comment As String = String.Empty
18
19     Private _Year As String = String.Empty
20
21     Private _Genre As String = String.Empty
22
23     Private _GenreID As Byte
24
25
26
27     Private Genres() As String = {"Blues", "Classic Rock", "Country", "Dance", "Disco", "Funk", "Grunge", _
28
29             "Hip-Hop", "Jazz", "Metal", "New Age", "Oldies", "Other", "Pop", "R&B", "Rap", "Reggae", "Rock", _
30
31             "Techno", "Industrial", "Alternative", "Ska", "Death Metal", "Pranks", "Soundtrack", "Euro-Techno", _
32
33             "Ambient", "Trip-Hop", "Vocal", "Jazz+Funk", "Fusion", "Trance", "Classical", "Instrumental", "Acid", _
34
35             "House", "Game", "Sound Clip", "Gospel", "Noise", "AlternRock", "Bass", "Soul", "Punk", "Space", _
36
37             "Meditative", "Instrumental Pop", "Instrumental Rock", "Ethnic", "Gothic", "Darkwave", "Techno-Industrial", _
38
39             "Electronic", "Pop-Folk", "Eurodance", "Dream", "Southern Rock", "Comedy", "Cult", "Gangsta", "Top 40", _
40
41             "Christian Rap", "Pop/Funk", "Jungle", "Native American", "Cabaret", "New Wave", "Psychedelic", "Rave", _
42
43             "Showtunes", "Trailer", "Lo-Fi", "Tribal", "Acid Punk", "Acid Jazz", "Polka", "Retro", "Musical", _
44
45             "Rock & Roll", "Hard Rock", "Folk", "Folk/Rock", "National Folk", "Swing", "Bebob", "Latin", "Revival", _
46
47             "Celtic", "Bluegrass", "Avantgarde", "Gothic Rock", "Progressive Rock", "Psychedelic Rock", "Symphonic Rock", _
48
49             "Slow Rock", "Big Band", "Chorus", "Easy Listening", "Acoustic", "Humour", "Speech", "Chanson", "Opera", _
50
51             "Chamber Music", "Sonata", "Symphony", "Booty Bass", "Primus", "Porn Groove", "Satire", "Slow Jam", "Club", _
52
53             "Tango", "Samba", "Folklore"}
54
55
56
57     Public Property MP3Tag() As String
58
59         Get
60
61             Return _MP3Tag
62
63         End Get
64
65         Set(ByVal value As String)
66
67             _MP3Tag = value.Trim
68
69         End Set
70
71     End Property
72
73
74
75     Public Property Title() As String
76
77         Get
78
79             Return _Title
80
81         End Get
82
83         Set(ByVal value As String)
84
85             _Title = value.Trim
86
87         End Set
88
89     End Property
90
91
92
93     Public Property Artist() As String
94
95         Get
96
97             Return _Artist
98
99         End Get
100
101         Set(ByVal value As String)
102
103             _Artist = value.Trim
104
105         End Set
106
107     End Property
108
109
110
111     Public Property Album() As String
112
113         Get
114
115             Return _Album
116
117         End Get
118
119         Set(ByVal value As String)
120
121             _Album = value.Trim
122
123         End Set
124
125     End Property
126
127
128
129     Public Property Comment() As String
130
131         Get
132
133             Return _Comment
134
135         End Get
136
137         Set(ByVal value As String)
138
139             _Comment = value.Trim
140
141         End Set
142
143     End Property
144
145
146
147     Public Property Genre() As String
148
149         Get
150
151             Return _Genre
152
153         End Get
154
155         Set(ByVal value As String)
156
157             _Genre = value.Trim
158
159         End Set
160
161     End Property
162
163
164
165     Public Property GenreID() As Byte
166
167         Get
168
169             Return _GenreID
170
171         End Get
172
173         Set(ByVal value As Byte)
174
175             _GenreID = value
176
177         End Set
178
179     End Property
180
181
182
183     Public Property Year() As String
184
185         Get
186
187             Return _Year
188
189         End Get
190
191         Set(ByVal value As String)
192
193             _Year = value.Trim
194
195         End Set
196
197 End Property
198
199 End Class
200
201
202
203        上面的類只包含了mp3歌曲信息對應的數據結構，我們還要為它添加具體讀取mp3文件信息的過程：
204
205
206
207     Public Function GetMp3FileInfo(ByVal fname As String) As Boolean
208
209
210
211         'Open the filestream
212
213         Dim msfile As FileStream
214
215         Try
216
217             msfile = New FileStream(fname, FileMode.Open, File access.Read, FileShare.ReadWrite)
218
219             If Not (msfile.CanRead) Then
220
221                 Throw New IO.IOException("無法讀取文件:" + fname)
222
223             End If
224
225         Catch Ex As Exception
226
227             Throw New IO.IOException("讀取文件發生錯誤！" + Ex.Message)
228
229         End Try
230
231
232
233         Dim ID3(TAGLEN - 1) As Byte
234
235         Dim BinReader As BinaryReader
236
237         Dim StrInfo As String
238
239
240
241         '使用BinaryReader來讀取信息
242
243         BinReader = New BinaryReader(msfile)
244
245
246
247         msfile.Position = 0
248
249         msfile.Seek(-TAGLEN, SeekOrigin.End)
250
251
252
253         StrInfo = CBytesToString(BinReader.ReadBytes(3))
254
255
256
257         '判斷標簽頭是否為 TAG
258
259         If StrInfo.ToUpper = "TAG" Then
260
261
262
263             '讀取標題信息
264
265             StrInfo = CBytesToString(BinReader.ReadBytes(30)).Replace(Chr(0), "")
266
267             _Title = StrInfo
268
269
270
271             '讀取藝術家信息
272
273             StrInfo = CBytesToString(BinReader.ReadBytes(30)).Replace(Chr(0), "")
274
275             _Artist = StrInfo
276
277
278
279             '讀取專輯信息
280
281             StrInfo = CBytesToString(BinReader.ReadBytes(30)).Replace(Chr(0), "")
282
283             _Album = StrInfo
284
285
286
287             '讀取出版年度信息
288
289             StrInfo = CBytesToString(BinReader.ReadBytes(4)).Replace(Chr(0), "")
290
291             _Year = StrInfo
292
293
294
295             '讀取備注信息
296
297             StrInfo = CBytesToString(BinReader.ReadBytes(30)).Replace(Chr(0), "")
298
299             _Comment = StrInfo
300
301
302
303             '讀取歌曲流派信息
304
305             _GenreID = BinReader.ReadByte
306
307
308
309         End If
310
311
312
313         BinReader.Close()
314
315         msfile.Close()
316
317
318
319     End Function
320
321
322
323     '用于轉換編碼, 防止出現中文亂碼
324
325     Private Function CBytesToString(ByVal Bytes() As Byte) As String
326
327         '注意這里需要對編碼進行處理, 防止出現亂碼
328
329         Dim GbCode As Encoding = Encoding.GetEncoding("gb2312")
330
331         If Bytes.Length > 0 Then
332
333             Return GbCode.GetString(Bytes)
334
335         Else
336
337             Return String.Empty
338
339         End If
340
341     End Function

我們可以用一個簡單的Console程序來說明，如何使用Mp3Info類。使用Visual Studio 2005 Express，創建一個Console程序：

1 Module Module1
2
3
4
5     Sub
6
7
8
9         Dim Mp3 As New Mp3Info("D:/Music/Top 40 Singles/39 Embrace - Natures Law.mp3")
10
11
12
13         Console.WriteLine("Title : " + Mp3.Title)
14
15         Console.WriteLine("Artist: " + Mp3.Artist)
16
17         Console.WriteLine("Album : " + Mp3.Album)
18
19         Console.Read()
20
21     End Sub
22
23
24 End Module