Skip to main content
Topic: Create ITC from JPG/PNG R&D Discussion (Read 4299 times) previous topic - next topic
0 Members and 1 Guest are viewing this topic.

Create ITC from JPG/PNG R&D Discussion

Hi All,

Couple of threads spawn from

http://www.hydrogenaudio.org/forums/index....st&p=531611
http://www.hydrogenaudio.org/forums/index....st&p=538491

made me think of putting up a R&D thread for attempting to create ITC (iTunes Cover) files from local JPG files. The need arises when users don't wish to embed artwork into their Audio files. Idea of this thread is to consolidate all the knowledgebase we have that will eventually help achieving the final goal.

I was having my best shot at today but still not seeing the light. I followed the articles:

http://www.waldoland.com/dev/Articles/ITCFileFormat.aspx
http://www.falsecognate.org/2007/01/deciph...nes_itc_fil.php

and came up with a VB.net class that creates a ITC file that gets parsed properly according to the the first URL.

Code: [Select]
imports System.IO
'
' Created by SharpDevelop.
' User: e80655
' Date: 2008-01-02
' Time: 11:02 AM
'
' To change this template use Tools | Options | Coding | Edit Standard Headers.
'

Public Class cITCgen

Private mFilePath As String = String.Empty
private mLibraryPID as String = string.Empty

Public Sub New(libraryPID as String, imagePath As String)

mFilePath = imagePath
mLibraryPID = libraryPID

End Sub

public Sub Save(trackID as String)

Dim baseDir As String = path.Combine( environment.GetFolderPath(Environment.SpecialFolder.MyMusic), "iTunes\Album Artwork\Local\"+mLibraryPID)

dim sb as New System.Text.StringBuilder
For i As Integer = 1 To 3
sb.Append(Convert.ToInt32(trackId(trackId.Length-i), 16).ToString("00"))
sb.Append(Path.DirectorySeparatorChar)
Next

Dim artworkDir As String = path.Combine(baseDir, sb.ToString)

If directory.Exists(artworkDir) = False Then
directory.CreateDirectory(artworkDir)
End If

dim artworkName as String = string.Format("{0}-{1}.itc", mLibraryPID, trackID)
Dim artworkPath As String = Path.Combine(artworkDir, artworkName)

Process.Start(Path.GetDirectoryName(artworkPath))

dim artworkStream as Stream = File.Create(artworkPath)
Dim bw As New BinaryWriter(artworkStream)

' 1 to 4
bw.Write(Convert.ToByte(Convert.ToInt32("00", 16)))
bw.Write(Convert.ToByte(Convert.ToInt32("00", 16)))
bw.Write(Convert.ToByte(Convert.ToInt32("01", 16)))
bw.Write(Convert.ToByte(Convert.ToInt32("1c", 16)))

' 5 to 8
bw.Write(Convert.ToByte(Convert.ToInt32("69", 16)))
bw.Write(Convert.ToByte(Convert.ToInt32("74", 16)))
bw.Write(Convert.ToByte(Convert.ToInt32("63", 16)))
bw.Write(Convert.ToByte(Convert.ToInt32("68", 16)))

' bytes 9-24: purpose unknown.
For i As Integer = 1 To 3
bw.Write(Convert.ToByte(Convert.ToInt32("00", 16)))
bw.Write(Convert.ToByte(Convert.ToInt32("00", 16)))
bw.Write(Convert.ToByte(Convert.ToInt32("00", 16)))
bw.Write(Convert.ToByte(Convert.ToInt32("02", 16)))
Next
For i As Integer = 1 To 4
bw.Write(Convert.ToByte(Convert.ToInt32("00", 16)))
Next

' bytes 25-28 (chars): purpose unknown.
' Spells out "artw" (artwork?).
bw.Write(Convert.ToByte(Convert.ToInt32("61", 16)))
bw.Write(Convert.ToByte(Convert.ToInt32("72", 16)))
bw.Write(Convert.ToByte(Convert.ToInt32("74", 16)))
bw.Write(Convert.ToByte(Convert.ToInt32("77", 16)))

' In all cases seen so far, it is 256 consecutive null bytes (00).
For i As Integer = 1 To 256
bw.Write(Convert.ToByte(Convert.ToInt32("00", 16)))
Next

Dim fi As New FileInfo(mFilePath)
Dim b() As Byte = BitConverter.GetBytes(fi.Length - 284)
bw.Write(b(3))
bw.Write(b(2))
bw.Write(b(1))
bw.Write(b(0))

' bytes 289-292 (chars): purpose unknown.
' Spells out "item".
bw.Write(Convert.ToByte(Convert.ToInt32("69", 16)))
bw.Write(Convert.ToByte(Convert.ToInt32("74", 16)))
bw.Write(Convert.ToByte(Convert.ToInt32("65", 16)))
bw.Write(Convert.ToByte(Convert.ToInt32("6d", 16)))

' bytes 293-296 (unsigned 32-bit integer):
' variable that self-describes the offset to
' the beginning of the image stream from the beginning of section 2.
bw.Write(Convert.ToByte(Convert.ToInt32("00", 16)))
bw.Write(Convert.ToByte(Convert.ToInt32("00", 16)))
bw.Write(Convert.ToByte(Convert.ToInt32("00", 16)))
bw.Write(Convert.ToByte(Convert.ToInt32("d8", 16)))

' Immediately following the Data Header length is 16 bytes of disposable information.
For i As Integer = 1 To 4
bw.Write(Convert.ToByte(Convert.ToInt32("00", 16)))
bw.Write(Convert.ToByte(Convert.ToInt32("00", 16)))
bw.Write(Convert.ToByte(Convert.ToInt32("00", 16)))
bw.Write(Convert.ToByte(Convert.ToInt32("01", 16)))
Next

For i As Integer = 1 To 4
bw.Write(Convert.ToByte(Convert.ToInt32("00", 16)))
Next

' Library Persistent ID (8 bytes)
Dim s As String = String.Empty
For i As Integer = 0 To mLibraryPID.Length - 2
s = String.Concat(mLibraryPID(i), mLibraryPID(i + 1))
i += 1
bw.Write(Convert.ToByte(Convert.ToInt32(s, 16)))
Next

' Track Persistent ID (8 bytes)
For i As Integer = 0 To trackID.Length - 2
s = String.Concat(trackID(i), trackID(i + 1))
i += 1
Console.WriteLine(s)
bw.Write(Convert.ToByte(Convert.ToInt32(s, 16)))
Next

' Download/persistence indicator (4 bytes)
bw.Write(Convert.ToByte(Convert.ToInt32("6c", 16)))
bw.Write(Convert.ToByte(Convert.ToInt32("6f", 16)))
bw.Write(Convert.ToByte(Convert.ToInt32("63", 16)))
bw.Write(Convert.ToByte(Convert.ToInt32("6c", 16)))

' Pseudo-File Format (4 bytes)
Dim ext As String = Path.GetExtension(mFilePath).ToLower
If ext.Equals(".png") Then
bw.Write(Convert.ToByte(Convert.ToInt32("50", 16)))
bw.Write(Convert.ToByte(Convert.ToInt32("4e", 16)))
bw.Write(Convert.ToByte(Convert.ToInt32("47", 16)))
bw.Write(Convert.ToByte(Convert.ToInt32("66", 16)))
Else
bw.Write(Convert.ToByte(Convert.ToInt32("00", 16)))
bw.Write(Convert.ToByte(Convert.ToInt32("00", 16)))
bw.Write(Convert.ToByte(Convert.ToInt32("00", 16)))
bw.Write(Convert.ToByte(Convert.ToInt32("0d", 16)))
End If

' 00 00 00 03
bw.Write(Convert.ToByte(Convert.ToInt32("00", 16)))
bw.Write(Convert.ToByte(Convert.ToInt32("00", 16)))
bw.Write(Convert.ToByte(Convert.ToInt32("00", 16)))
bw.Write(Convert.ToByte(Convert.ToInt32("03", 16)))

' The next four bytes are an unsigned integer value indicating the width of the embedded image.

Dim bp As Image = Bitmap.FromFile(mFilePath)
b = BitConverter.GetBytes(bp.Width)
bw.Write(b(3))
bw.Write(b(2))
bw.Write(b(1))
bw.Write(b(0))

b = BitConverter.GetBytes(bp.Height)
bw.Write(b(3))
bw.Write(b(2))
bw.Write(b(1))
bw.Write(b(0))
bp.Dispose

' bytes 349-360: purpose unknown.
For i As Integer = 1 To 4
bw.Write(Convert.ToByte(Convert.ToInt32("00", 16))) '349, 350, 351, 352
Next
bw.Write(Convert.ToByte(Convert.ToInt32("00", 16))) ' 353
bw.Write(Convert.ToByte(Convert.ToInt32("00", 16))) ' 354
bw.Write(Convert.ToByte(Convert.ToInt32("d9", 16))) ' 355
bw.Write(Convert.ToByte(Convert.ToInt32("d9", 16))) ' 356

bw.Write(Convert.ToByte(Convert.ToInt32("8a", 16))) ' 357
bw.Write(Convert.ToByte(Convert.ToInt32("65", 16))) ' 358
bw.Write(Convert.ToByte(Convert.ToInt32("00", 16))) ' 359
bw.Write(Convert.ToByte(Convert.ToInt32("01", 16))) ' 360

' bytes 361-488: purpose unknown.
' In most cases seen so far, this is a string of null bytes.
For i As Integer = 1 To 128
bw.Write(Convert.ToByte(Convert.ToInt32("00", 16)))
Next

' bytes 489-492: purpose unknown.
' In all cases viewed, spells "data". Probably used as the header end marker.
bw.Write(Convert.ToByte(Convert.ToInt32("64", 16))) ' d
bw.Write(Convert.ToByte(Convert.ToInt32("61", 16))) ' a
bw.Write(Convert.ToByte(Convert.ToInt32("74", 16))) ' t
bw.Write(Convert.ToByte(Convert.ToInt32("61", 16))) ' a

For i As Integer = 1 To 4
bw.Write(Convert.ToByte(Convert.ToInt32("00", 16))) '
Next

bw.Write(file.ReadAllBytes(mFilePath))


bw.Close

End Sub

'
' Filename is two sixteen character hexadecimal strings tied together with a hyphen
' followed by the filename extension .itc. The first hexadecimal string is always
' the Library Persistent ID (can be seen in the iTunes Music Library.xml file).
' The second hexadecimal string is the Track Persistent ID _if_ the file is located
' in the Local subfolder hierarchy of the Album Artwork folder.
'
' Directory structure: On a Mac, the files will reside in: ~/Music/iTunes/Album Artwork/
' This folder has two subfolders, Download/ and Local/. Inside each of these folders
' will be one folder with the Library Persistent ID as its name. I assume that if
' you have multiple iTunes libraries, there will be additional folders with the
' corresponding Library Persistent IDs.
'
' Then you must traverse three layers of folders, each with two digit decimal labels,
' corresponding in reverse order to the last three hexadecimal digits prior to the
' .itc filename extension. e.g., if your downloaded .itc file ends with A01.itc, it
' will reside in:
' ~/Music/iTunes/Album Artwork/Download/"Library Persistent ID"/01/00/10/fooA01.itc

' for 3D82AC91DD2D58B0 as library id and 3D82AC91DD2D58B0 as trackID
' the path would be consideering 8B0 => 0/B/8 = 00/11/08
' /Music/iTunes/Album Artwork/Local/3D82AC91DD2D58B0/00/11/08/3D82AC91DD2D58B0-3D82AC91DD2D58B0.itc

End Class

The usage will be simply like:

Code: [Select]
    Sub Button1Click(sender As Object, e As EventArgs)
        
        Dim dlg As New OpenFileDialog
        dlg.Filter = "Artwork files (*.jpg)|*.jpg"
        If dlg.ShowDialog = dialogresult.OK Then
            Dim libID As String = "3D82AC91DD2D58B0"
            Dim itc As New cITCgen(libID, dlg.FileName)
            Dim trackID As String = "3D82AC91DD2D58B0"
            itc.Save (trackID)
        End If
        
    End Sub

For those interested, please try it out, add/modify/enhance/contribute back to the discussion.

Thanks, 
McoreD

[!--sizeo:1--][span style=\"font-size:8pt;line-height:100%\"][!--/sizeo--]Moderation: code changed to codebox.[/size]

 
SimplePortal 1.0.0 RC1 © 2008-2019