Script to transform Apple iTunes' .itc files into images (JPG or PNG)

itcToImageV2.1.sh

#!/bin/bash
# Script to transform Apple iTunes' .itc files into images (JPG or PNG)
#
# This is a mod of the very useful script by Matthieu Riegler (@kyro38) at 
#    https://github.com/kyro38/MiscStuff/blob/master/Useless/itc/itcToImageV2.sh
#
# The mods are 
#    * to use `find` rather than `gfind` (I'm on a Mac and find` works just fine 
#      and I don't need to install `coreutils` just for this task)
#    * to parameterize the source and destination directories for the .itc files
#    * to add some communication with the user
#    * to count the ITC files being processed in order to get a confirmation from the user
#
# My iTunes folder is usually nonstandard, I want to be able to run this on Album Artwork
# folders copied from others' machines (who don't want me hogging their machine for this
# effort), and I'm not consistent on my own machines whether I use the standard directory
# structure for iTunes.
#
# .itc files may be located in ~/Music/iTunes/Album Artwork unless you, like I,
#    have customized iTunes' directory
#
# This script uses (/!\ needs ) ImageMagick's convert, hexdump, printf and dd.
#
# "Newer" (>2012?) iTunes ITC files may contain ARGB content, with as many as 3 sizes 
#    of the same image in one ITC file. Because of that, and depending on the size 
#    of your artwork directory, this script might be a little slow. One alternative 
#    is Simon Kennedy's Python module: http://www.sffjunkie.co.uk/python-itc.html
#
# Have a nice day.

# Test for inputs, use defaults if absent
if [ -z $1 ]; then
	# absent any parameters, use defaults
	AlbumArtwork="${HOME}/Music/iTunes/Album Artwork"
	DestinationDir="$AlbumArtwork/Images"
	echo
	echo "Using default directories:"
	echo "    Source:     " $AlbumArtwork
	echo "    Destination:" $DestinationDir
else
	# Source dir
	AlbumArtwork=$1
	# Destination dir
	DestinationDir=$2
	echo
	echo "Using these directories:"
	echo "    Source:     " $AlbumArtwork
	echo "    Destination:" $DestinationDir
	echo
fi

# Get count of ITC files for notice to script executor
FileCount=`find "$AlbumArtwork" -name '*.itc' | wc -l`

read -r -p "About to extract all art from
    $AlbumArtwork
to
    $DestinationDir.

There are $FileCount .itc files to be processed.

Continue (y/n)? " choice
case "$choice" in 
  y|Y )
    echo "OK! Here we go."
    ;;
  n|N )
    echo "Abandoning script."
    exit 1
    ;;
  * )
    echo "Invalid response, exiting."
    exit 1
    ;;
esac

IFS=$'\n'

if [ ! -d "$DestinationDir" ]; then
	mkdir "$DestinationDir"
	echo "new Images dir"
fi

for file in `find "$AlbumArtwork" -name '*.itc'`; do
	start=0x11C
	exit=0;
	i=1;
	echo $file
	while [ 1 ]; do

		typeOffset=$(($start+0x30))
		imageType=$(hexdump -n 4 -s $typeOffset -e '"0x"4/1 "%02x" "\n"' $file)

		#If there is no next byte, jump to the next itc file.
		if [[ -z $imageType ]]; then
			break
		fi

		imageOffsetOffset=$(($start+8))

		itemSize=$(hexdump -n 4 -s $start -e '"0x"4/1 "%02x" "\n"' $file)
		imageOffset=$(hexdump -n 4 -s $imageOffsetOffset -e '"0x"4/1 "%02x" "\n"' $file)

		imageStart=$(($start+$imageOffset))
		imageSize=$(($itemSize-imageOffset))

		imageWidth=$(hexdump -n 4 -s $(($start+56)) -e '"0x"4/1 "%02x" "\n"' $file)
		imageWidth=$(printf "%d" $imageWidth)
		imageHeight=$(hexdump -n 4 -s $(($start+60)) -e '"0x"4/1 "%02x" "\n"' $file)
		imageHeight=$(printf "%d" $imageHeight)

		dir=$(dirname "$file")
		xbase=${file##*/} #file.etc
		xpref=${xbase%.*} #file prefix

		#echo $file
		#echo itemsize $itemSize
		#echo start $start
		#echo imageOffset $imageOffset
		#echo imageStart $imageStart
		#echo imageSize $imageSize
		#echo imageWidth $imageWidth
		#echo imageHeight $imageHeight

		if [[ $imageType -eq 0x504E4766 ]] || [[ $imageType -eq 0x0000000E ]] ; then
			targetFile="$DestinationDir/$xpref-$i.png"
			if [ ! -f "$targetFile" ]; then
				echo PNG
				dd skip=$imageStart count=$imageSize if="$file" of="$targetFile" bs=1 &> /dev/null
			fi
		elif [[ $imageType -eq 0x41524762 ]] ; then
			targetFile="$DestinationDir/$xpref-$i.png"
			if [ ! -f "$targetFile" ]; then
				echo ARGB
				dd skip=$imageStart count=$imageSize if="$file" of="$TMPDIR/test$i" bs=1 &> /dev/null

				#Using a matrix to convert ARGB to RGBA since imagemagick does only support rgba input
				convert -size $imageWidth"x"$imageHeight -depth 8 -color-matrix '0 1 0 0 0 0 1 0 0 0 0 1 1 0 0 0' rgba:"$TMPDIR/test$i" "$targetFile"
			fi
		elif [[ $imageType -eq 0x0000000D ]] ; then
			targetFile="$DestinationDir/$xpref-$i.jpg"
			if [ ! -f "$targetFile" ]; then
				echo JPG
				dd skip=$imageStart count=$imageSize if="$file" of="$targetFile" bs=1 &> /dev/null
			fi
		else
			echo $imageType
			exit=1
			break;
		fi

		start=$(($start+$itemSize))
		i=$(($i+1))
	done
done

Thanks for this script, it has been really helpful.

In my case, it fell into the else clause in line 146 (imageType was 0x00002328), so I decided to simply save it as a TIFF file and it worked seamlessly. Then I tried changed it to JPG or PNG and it still worked. So I assume that, as long as you give it a valid image extension, tools like Gimp are able to open it.

Glad it was useful for you! It's been so long since I looked at this that the original user's script is gone. My abilities extend only as far as modding the original, so if you have improvements a) they are most welcome and b) I'll need you to spell them out.

I made no improvement at all, I simply added your lines 141-145 under 147 in order to always save as JPG if the imageType is not recognized. In other words: make JPG the default extension, even when it does not match with the hexdump.

Got it -- thank you for that!