使用 TagLibSharp 读取 APEv2 mp3 标签？
Read APEv2 mp3 tag with TagLibSharp?
场景
我通常使用MP3Gain应用程序来设置mp3文件的回放增益。
应用程序可以在 mp3 文件的 APEv2 标签中创建这些字段：
（截图来自WinAmp玩家）
问题
使用 TagLibSharp 库我写了一个 ID3v1 和 ID3v2 解析器，现在，我想知道我是否可以使用这个库读写提到的 APEv2 字段？
研究
我认为 MP3Gain 应用程序使用字段的唯一名称，因此 TagLibsharp 可能不支持它们，但是，TagLibsharp 库有一个 ReadBlock()、Removeblock()、Find() 和 RFind() 方法，我认为这是我需要使用的方法，但我没有确切知道如何结合使用它们...
这是我仅有的：
Dim file As New TagLib.Mpeg.AudioFile("C:\input.mp3")
Dim data As Byte() = Encoding.ASCII.GetBytes("MP3GAIN_MINMAX")
Dim vector As New ByteVector(data)
Dim offset As Long = file.Find(vector)
这是用 Vb.Net 编写的伪代码，只是为了演示预期的抽象或行为。
Imports TagLib
Public NotInheritable Class Mp3File
Private tagFile As Global.TagLib.Mpeg.AudioFile
Public ReadOnly Property APEv2 As APEv2Tag
Get
Return Me.apeTagB
End Get
End Property
Private ReadOnly apeTagB As APEv2Tag
Public Sub New(ByVal file As FileInfo)
Me.tagFile = New Global.TagLib.Mpeg.AudioFile(file.FullName)
Me.apeTagB = New APEv2Tag(Me.tagFile)
End Sub
End Class
''' <summary>
''' Represents the APEv2 tag for a MP3 file.
''' </summary>
Public Class APEv2Tag
Protected ReadOnly mp3File As Global.TagLib.Mpeg.AudioFile
Public Sub New(ByVal mp3File As Global.TagLib.Mpeg.AudioFile)
Me.mp3File = mp3File
End Sub
Public Overridable Property MP3GAIN_MINMAX As Double
Get
If field exists then...
Return TheValue...
End If
End Get
Set(ByVal value As Double)
...
End Set
End Property
' More properties here...
End Class
更新：
我想我终于自己完成了 "Read" 部分，但是我不确定如何编写块，因为如果该字段不存在，我肯定可以 overwritte/corrupt 文件。 ..
''' ----------------------------------------------------------------------------------------------------
''' <summary>
''' Gets the <c>MP3GAIN_MINMAX</c> metatada field of the audio file.
''' </summary>
''' ----------------------------------------------------------------------------------------------------
''' <returns>
''' The <c>MP3GAIN_MINMAX</c> field value.
''' </returns>
''' ----------------------------------------------------------------------------------------------------
<DebuggerStepThrough>
Private Function GetFieldMP3GainMinMax() As String
Dim data As Byte() = Encoding.UTF8.GetBytes("MP3GAIN_MINMAX")
Dim vector As New ByteVector(data)
Dim offset As Long = Me.mp3File.Find(vector)
Dim result As String
If (offset = -1) Then
Return String.Empty
Else
Try
offset += ("MP3GAIN_MINMAX".Length + 1)
Me.mp3File.Seek(offset, SeekOrigin.Begin)
result = Me.mp3File.ReadBlock(8).ToString.TrimEnd()
Return result
Catch ex As Exception
Throw
Finally
Me.mp3File.Seek(0, SeekOrigin.Begin)
End Try
End If
End Function
''' ----------------------------------------------------------------------------------------------------
''' <summary>
''' Gets the <c>MP3GAIN_UNDO</c> metatada field of the audio file.
''' </summary>
''' ----------------------------------------------------------------------------------------------------
''' <returns>
''' The <c>MP3GAIN_UNDO</c> field value.
''' </returns>
''' ----------------------------------------------------------------------------------------------------
<DebuggerStepThrough>
Private Function GetFieldMP3GainUndo() As String
Dim data As Byte() = Encoding.UTF8.GetBytes("MP3GAIN_UNDO")
Dim vector As New ByteVector(data)
Dim offset As Long = Me.mp3File.Find(vector)
Dim result As String
If (offset = -1) Then
Return String.Empty
Else
Try
offset += ("MP3GAIN_UNDO".Length + 1)
Me.mp3File.Seek(offset, SeekOrigin.Begin)
result = Me.mp3File.ReadBlock(12).ToString.TrimEnd()
Return result
Catch ex As Exception
Throw
Finally
Me.mp3File.Seek(0, SeekOrigin.Begin)
End Try
End If
End Function
''' ----------------------------------------------------------------------------------------------------
''' <summary>
''' Gets the <c>REPLAYGAIN_TRACK_GAIN</c> metatada field of the audio file.
''' </summary>
''' ----------------------------------------------------------------------------------------------------
''' <returns>
''' The <c>REPLAYGAIN_TRACK_GAIN</c> field value.
''' </returns>
''' ----------------------------------------------------------------------------------------------------
<DebuggerStepThrough>
Private Function GetFieldReplayGainTrackGain() As String
Dim data As Byte() = Encoding.UTF8.GetBytes("REPLAYGAIN_TRACK_GAIN")
Dim vector As New ByteVector(data)
Dim offset As Long = Me.mp3File.Find(vector)
Dim result As String
If (offset = -1) Then
Return String.Empty
Else
Try
offset += ("REPLAYGAIN_TRACK_GAIN".Length + 1)
Me.mp3File.Seek(offset, SeekOrigin.Begin)
result = Me.mp3File.ReadBlock(12).ToString.TrimEnd()
Return result
Catch ex As Exception
Throw
Finally
Me.mp3File.Seek(0, SeekOrigin.Begin)
End Try
End If
End Function
''' ----------------------------------------------------------------------------------------------------
''' <summary>
''' Gets the <c>REPLAYGAIN_TRACK_PEAK</c> metatada field of the audio file.
''' </summary>
''' ----------------------------------------------------------------------------------------------------
''' <returns>
''' The <c>REPLAYGAIN_TRACK_PEAK</c> field value.
''' </returns>
''' ----------------------------------------------------------------------------------------------------
<DebuggerStepThrough>
Private Function GetFieldReplayGainTrackPeak() As String
Dim data As Byte() = Encoding.UTF8.GetBytes("REPLAYGAIN_TRACK_PEAK")
Dim vector As New ByteVector(data)
Dim offset As Long = Me.mp3File.Find(vector)
Dim result As String
If (offset = -1) Then
Return String.Empty
Else
Try
offset += ("REPLAYGAIN_TRACK_PEAK".Length + 1)
Me.mp3File.Seek(offset, SeekOrigin.Begin)
result = Me.mp3File.ReadBlock(8).ToString.TrimEnd()
Return result
Catch ex As Exception
Throw
Finally
Me.mp3File.Seek(0, SeekOrigin.Begin)
End Try
End If
End Function
从 TagLib# 文件获取 APEv2 特定信息的过程类似于 this answer.
中描述的 ID3v2 标签的过程
读取值的方法如下：
// Get the APEv2 tag if it exists.
TagLib.Ape.Tag ape_tag = (TagLib.Ape.Tag)file.GetTag(TagLib.TagTypes.Ape, false);
if(ape_tag != null) {
// Get the item.
TagLib.Ape.Item item = ape_tag.GetItem("MP3GAIN_MINMAX");
if (item != null) {
Console.Log(item.ToStringArray());
}
}
根据屏幕截图，我不确定该字段是单个字符串还是用逗号连接的两个字符串。
保存是相反的方向，但更简单一些：
// Get the APEv2 tag if it exists.
TagLib.Ape.Tag ape_tag = (TagLib.Ape.Tag)file.GetTag(TagLib.TagTypes.Ape, true);
if(ape_tag != null) {
ape_tag.SetValue("MP3GAIN_MINMAX", value);
}
file.Save();
一个例子，对于Vb.Net：
字段：
ReadOnly mp3File As Global.TagLib.Mpeg.AudioFile = ...
属性（MP3Gain相关）：
Property MP3GainMinMax As String
Get
Return Me.GetField("MP3GAIN_MINMAX")
End Get
Set(ByVal value As String)
Me.SetField("MP3GAIN_MINMAX", value)
End Set
End Property
Property MP3GainUndo As String
Get
Return Me.GetField("MP3GAIN_UNDO")
End Get
Set(ByVal value As String)
Me.SetField("MP3GAIN_UNDO", value)
End Set
End Property
Property ReplayGainTrackGain As String
Get
Return Me.GetField("REPLAYGAIN_TRACK_GAIN")
End Get
Set(ByVal value As String)
Me.SetField("REPLAYGAIN_TRACK_GAIN", value)
End Set
End Property
Property ReplayGainTrackPeak As String
Get
Return Me.GetField("REPLAYGAIN_TRACK_PEAK")
End Get
Set(ByVal value As String)
Me.SetField("REPLAYGAIN_TRACK_PEAK", value)
End Set
End Property
函数'Get':
Function GetField(ByVal fieldName As String) As String
Dim apeTag As TagLib.Ape.Tag =
DirectCast(Me.mp3File.GetTag(TagTypes.Ape, create:=False), TagLib.Ape.Tag)
If (apeTag IsNot Nothing) Then
Dim item As TagLib.Ape.Item = apeTag.GetItem(fieldName)
If (item IsNot Nothing) Then
Return item.ToString()
End If
End If
Return String.Empty
End Function
方法'Set':
Sub SetField(ByVal fieldName As String, ByVal value As String)
Dim apeTag As TagLib.Ape.Tag =
DirectCast(Me.mp3File.GetTag(TagTypes.Ape, create:=True), TagLib.Ape.Tag)
apeTag.SetValue(fieldName, value)
End Sub
场景
我通常使用MP3Gain应用程序来设置mp3文件的回放增益。
应用程序可以在 mp3 文件的 APEv2 标签中创建这些字段：
（截图来自WinAmp玩家）
问题
使用 TagLibSharp 库我写了一个 ID3v1 和 ID3v2 解析器，现在，我想知道我是否可以使用这个库读写提到的 APEv2 字段？
研究
我认为 MP3Gain 应用程序使用字段的唯一名称，因此 TagLibsharp 可能不支持它们，但是，TagLibsharp 库有一个 ReadBlock()、Removeblock()、Find() 和 RFind() 方法，我认为这是我需要使用的方法，但我没有确切知道如何结合使用它们...
这是我仅有的：
Dim file As New TagLib.Mpeg.AudioFile("C:\input.mp3")
Dim data As Byte() = Encoding.ASCII.GetBytes("MP3GAIN_MINMAX")
Dim vector As New ByteVector(data)
Dim offset As Long = file.Find(vector)
这是用 Vb.Net 编写的伪代码，只是为了演示预期的抽象或行为。
Imports TagLib
Public NotInheritable Class Mp3File
Private tagFile As Global.TagLib.Mpeg.AudioFile
Public ReadOnly Property APEv2 As APEv2Tag
Get
Return Me.apeTagB
End Get
End Property
Private ReadOnly apeTagB As APEv2Tag
Public Sub New(ByVal file As FileInfo)
Me.tagFile = New Global.TagLib.Mpeg.AudioFile(file.FullName)
Me.apeTagB = New APEv2Tag(Me.tagFile)
End Sub
End Class
''' <summary>
''' Represents the APEv2 tag for a MP3 file.
''' </summary>
Public Class APEv2Tag
Protected ReadOnly mp3File As Global.TagLib.Mpeg.AudioFile
Public Sub New(ByVal mp3File As Global.TagLib.Mpeg.AudioFile)
Me.mp3File = mp3File
End Sub
Public Overridable Property MP3GAIN_MINMAX As Double
Get
If field exists then...
Return TheValue...
End If
End Get
Set(ByVal value As Double)
...
End Set
End Property
' More properties here...
End Class
更新：
我想我终于自己完成了 "Read" 部分，但是我不确定如何编写块，因为如果该字段不存在，我肯定可以 overwritte/corrupt 文件。 ..
''' ----------------------------------------------------------------------------------------------------
''' <summary>
''' Gets the <c>MP3GAIN_MINMAX</c> metatada field of the audio file.
''' </summary>
''' ----------------------------------------------------------------------------------------------------
''' <returns>
''' The <c>MP3GAIN_MINMAX</c> field value.
''' </returns>
''' ----------------------------------------------------------------------------------------------------
<DebuggerStepThrough>
Private Function GetFieldMP3GainMinMax() As String
Dim data As Byte() = Encoding.UTF8.GetBytes("MP3GAIN_MINMAX")
Dim vector As New ByteVector(data)
Dim offset As Long = Me.mp3File.Find(vector)
Dim result As String
If (offset = -1) Then
Return String.Empty
Else
Try
offset += ("MP3GAIN_MINMAX".Length + 1)
Me.mp3File.Seek(offset, SeekOrigin.Begin)
result = Me.mp3File.ReadBlock(8).ToString.TrimEnd()
Return result
Catch ex As Exception
Throw
Finally
Me.mp3File.Seek(0, SeekOrigin.Begin)
End Try
End If
End Function
''' ----------------------------------------------------------------------------------------------------
''' <summary>
''' Gets the <c>MP3GAIN_UNDO</c> metatada field of the audio file.
''' </summary>
''' ----------------------------------------------------------------------------------------------------
''' <returns>
''' The <c>MP3GAIN_UNDO</c> field value.
''' </returns>
''' ----------------------------------------------------------------------------------------------------
<DebuggerStepThrough>
Private Function GetFieldMP3GainUndo() As String
Dim data As Byte() = Encoding.UTF8.GetBytes("MP3GAIN_UNDO")
Dim vector As New ByteVector(data)
Dim offset As Long = Me.mp3File.Find(vector)
Dim result As String
If (offset = -1) Then
Return String.Empty
Else
Try
offset += ("MP3GAIN_UNDO".Length + 1)
Me.mp3File.Seek(offset, SeekOrigin.Begin)
result = Me.mp3File.ReadBlock(12).ToString.TrimEnd()
Return result
Catch ex As Exception
Throw
Finally
Me.mp3File.Seek(0, SeekOrigin.Begin)
End Try
End If
End Function
''' ----------------------------------------------------------------------------------------------------
''' <summary>
''' Gets the <c>REPLAYGAIN_TRACK_GAIN</c> metatada field of the audio file.
''' </summary>
''' ----------------------------------------------------------------------------------------------------
''' <returns>
''' The <c>REPLAYGAIN_TRACK_GAIN</c> field value.
''' </returns>
''' ----------------------------------------------------------------------------------------------------
<DebuggerStepThrough>
Private Function GetFieldReplayGainTrackGain() As String
Dim data As Byte() = Encoding.UTF8.GetBytes("REPLAYGAIN_TRACK_GAIN")
Dim vector As New ByteVector(data)
Dim offset As Long = Me.mp3File.Find(vector)
Dim result As String
If (offset = -1) Then
Return String.Empty
Else
Try
offset += ("REPLAYGAIN_TRACK_GAIN".Length + 1)
Me.mp3File.Seek(offset, SeekOrigin.Begin)
result = Me.mp3File.ReadBlock(12).ToString.TrimEnd()
Return result
Catch ex As Exception
Throw
Finally
Me.mp3File.Seek(0, SeekOrigin.Begin)
End Try
End If
End Function
''' ----------------------------------------------------------------------------------------------------
''' <summary>
''' Gets the <c>REPLAYGAIN_TRACK_PEAK</c> metatada field of the audio file.
''' </summary>
''' ----------------------------------------------------------------------------------------------------
''' <returns>
''' The <c>REPLAYGAIN_TRACK_PEAK</c> field value.
''' </returns>
''' ----------------------------------------------------------------------------------------------------
<DebuggerStepThrough>
Private Function GetFieldReplayGainTrackPeak() As String
Dim data As Byte() = Encoding.UTF8.GetBytes("REPLAYGAIN_TRACK_PEAK")
Dim vector As New ByteVector(data)
Dim offset As Long = Me.mp3File.Find(vector)
Dim result As String
If (offset = -1) Then
Return String.Empty
Else
Try
offset += ("REPLAYGAIN_TRACK_PEAK".Length + 1)
Me.mp3File.Seek(offset, SeekOrigin.Begin)
result = Me.mp3File.ReadBlock(8).ToString.TrimEnd()
Return result
Catch ex As Exception
Throw
Finally
Me.mp3File.Seek(0, SeekOrigin.Begin)
End Try
End If
End Function
从 TagLib# 文件获取 APEv2 特定信息的过程类似于 this answer.
中描述的 ID3v2 标签的过程读取值的方法如下：
// Get the APEv2 tag if it exists.
TagLib.Ape.Tag ape_tag = (TagLib.Ape.Tag)file.GetTag(TagLib.TagTypes.Ape, false);
if(ape_tag != null) {
// Get the item.
TagLib.Ape.Item item = ape_tag.GetItem("MP3GAIN_MINMAX");
if (item != null) {
Console.Log(item.ToStringArray());
}
}
根据屏幕截图，我不确定该字段是单个字符串还是用逗号连接的两个字符串。
保存是相反的方向，但更简单一些：
// Get the APEv2 tag if it exists.
TagLib.Ape.Tag ape_tag = (TagLib.Ape.Tag)file.GetTag(TagLib.TagTypes.Ape, true);
if(ape_tag != null) {
ape_tag.SetValue("MP3GAIN_MINMAX", value);
}
file.Save();
一个例子，对于Vb.Net：
字段：
ReadOnly mp3File As Global.TagLib.Mpeg.AudioFile = ...
属性（MP3Gain相关）：
Property MP3GainMinMax As String
Get
Return Me.GetField("MP3GAIN_MINMAX")
End Get
Set(ByVal value As String)
Me.SetField("MP3GAIN_MINMAX", value)
End Set
End Property
Property MP3GainUndo As String
Get
Return Me.GetField("MP3GAIN_UNDO")
End Get
Set(ByVal value As String)
Me.SetField("MP3GAIN_UNDO", value)
End Set
End Property
Property ReplayGainTrackGain As String
Get
Return Me.GetField("REPLAYGAIN_TRACK_GAIN")
End Get
Set(ByVal value As String)
Me.SetField("REPLAYGAIN_TRACK_GAIN", value)
End Set
End Property
Property ReplayGainTrackPeak As String
Get
Return Me.GetField("REPLAYGAIN_TRACK_PEAK")
End Get
Set(ByVal value As String)
Me.SetField("REPLAYGAIN_TRACK_PEAK", value)
End Set
End Property
函数'Get':
Function GetField(ByVal fieldName As String) As String
Dim apeTag As TagLib.Ape.Tag =
DirectCast(Me.mp3File.GetTag(TagTypes.Ape, create:=False), TagLib.Ape.Tag)
If (apeTag IsNot Nothing) Then
Dim item As TagLib.Ape.Item = apeTag.GetItem(fieldName)
If (item IsNot Nothing) Then
Return item.ToString()
End If
End If
Return String.Empty
End Function
方法'Set':
Sub SetField(ByVal fieldName As String, ByVal value As String)
Dim apeTag As TagLib.Ape.Tag =
DirectCast(Me.mp3File.GetTag(TagTypes.Ape, create:=True), TagLib.Ape.Tag)
apeTag.SetValue(fieldName, value)
End Sub