Read MP3 header information and read/write the ID3v1 tag

• Download source code - 61 Kb
• Download compiled help file - 32 Kb

Introduction

There are many other articles at The Code Project describing the audio header and tag information, but none in VB.NET. So it's time to update my very old article (Reading and writing MP3 ID3v1 tags ) with nicer code and extend it to read the MPEG header information.

I don't want to go into detail about the structure of MPEG audio headers, because Konrad Windszus already has a very good article (MPEG Audio Frame Header) about that. If you're interested in the structure of the audio header or the ID3 tag format i recommend to visit the following sites:

• http://www.mp3-tech.org
• http://www.mp3-converter.com/mp3codec/mp3_anatomy.htm
• http://www.getid3.org
• http://www.codeguru.com/vb/gen/vb_multimedia/mp3s/article.php
• http://www.multiweb.cz/twoinches/MP3inside.htm
• http://gabriel.mp3-tech.org/mp3infotag.html
• http://www.id3.org/id3v1.html

Using the code

I wrote two classes to handle the header and tag information, called MP3Info and ID3v1Tag. The following code will show the structure to use the classes:

Dim objMP3Info As New _
 Monotic.Multimedia.MP3.MP3Info
With ListView1
    ''' Set the filename property
    objMP3Info.Filename = "c:\test.mp3"

    ''' Add the header information to a listview
    .Add("Filesize").SubItems.Add(objMP3Info.Filesize & " Byte")
    .Add("SamplingRateFrequency").SubItems.Add _
     (objMP3Info.SamplingRateFrequency & " Hz")
    .Add("Padding").SubItems.Add(objMP3Info.Padding & " Bytes")
    .Add("Private").SubItems.Add(objMP3Info.PrivateBit)
    .Add("Copyright").SubItems.Add(objMP3Info.Copyright)
    .Add("OriginalBit").SubItems.Add(objMP3Info.OriginalBit)
    .Add("Bitrate").SubItems.Add(objMP3Info.Bitrate & " bps")
    .Add("FrameSamples").SubItems.Add(objMP3Info.FrameSamples)
    .Add("FrameSize").SubItems.Add(objMP3Info.FrameSize & " Byte")
    .Add("Length").SubItems.Add(objMP3Info.Length & " s (" 
     & Int(objMP3Info.Length / 60) & ":" & _
      objMP3Info.Length Mod 60 & " m)")
    .Add("HeaderPosition").SubItems.Add(objMP3Info.HeaderPosition)
    .Add("VBRScale").SubItems.Add(objMP3Info.VBRScale)

    Select Case objMP3Info.MPEGVersion
        Case MP3.MPEGVersionEnum.MPEG1
            .Add("MPEGType").SubItems.Add("MPEG 1")
        Case MP3.MPEGVersionEnum.MPEG2
            .Add("MPEGType").SubItems.Add("MPEG 2")
        Case MP3.MPEGVersionEnum.MPEG25
            .Add("MPEGType").SubItems.Add("MPEG 2.5")
    End Select

    Select Case objMP3Info.Layer
        Case MP3.LayerEnum.LayerI
            .Add("Layer").SubItems.Add("Layer I")
        Case MP3.LayerEnum.LayerII
            .Add("Layer").SubItems.Add("Layer II")
        Case MP3.LayerEnum.LayerIII
            .Add("Layer").SubItems.Add("Layer III")
    End Select

    Select Case objMP3Info.Protection
        Case MP3.ProtectionEnum.None
            .Add("Protection").SubItems.Add("None")
        Case MP3.ProtectionEnum.CRC
            .Add("Protection").SubItems.Add("By CRC")
    End Select

    Select Case objMP3Info.ChannelMode
        Case MP3.ChannelModeEnum.DualChannel
            .Add("ChannelMode").SubItems.Add("Dual Channel")
        Case MP3.ChannelModeEnum.JointStereo
            .Add("ChannelMode").SubItems.Add("Joint Stereo")
        Case MP3.ChannelModeEnum.SingleChannel
            .Add("ChannelMode").SubItems.Add("Single Channel")
        Case MP3.ChannelModeEnum.Stereo
            .Add("ChannelMode").SubItems.Add("Stereo")
    End Select

    Select Case objMP3Info.Emphasis
        Case MP3.EmphasisEnum.CCIT
            .Add("Emphasis").SubItems.Add("CCIT")
        Case MP3.EmphasisEnum.MS5015
            .Add("Emphasis").SubItems.Add("50/15 ms")
        Case MP3.EmphasisEnum.None
            .Add("Emphasis").SubItems.Add("None")
    End Select

    Select Case objMP3Info.Encoding
        Case MP3.EncodingEnum.CBR
            .Add("Encoding").SubItems.Add("CBR")
        Case MP3.EncodingEnum.VBR
            .Add("Encoding").SubItems.Add("VBR")
    End Select

    ''' Add the ID3v1 tag information to a listview
    If (objMP3Info.ID3v1Tag.TagAvailable) Then
        .Add("ID3 Title").SubItems.Add _
         (objMP3Info.ID3v1Tag.Title)
        [...]
    End If

    ''' Update the tag
    objMP3Info.ID3v1Tag.Title = "Another title"
    objMP3Info.ID3v1Tag.Update()

End With

Please have a look at the sample and the class code to see all the features.

Points of Interest

Unlike other articles, this class will handle CBR and VBR encoded files, so the playtime is calculated correctly.

The class is well-commented with XML comments made by AxTools CodeSmart 2005 and NDoc . I included the generated HTML help file in the download.

I'm working on reading and writing the much more complex ID3v2.x tags at the moment (80% done, just compressed frames are a little bit tricky). If you are interested in this, i will update this article in the future.

History

27.02.2004 Release of version 1

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