<?xml version="1.0" encoding="utf-8"?><!DOCTYPE article  PUBLIC '-//OASIS//DTD DocBook XML V4.4//EN'  'http://www.docbook.org/xml/4.4/docbookx.dtd'><article><articleinfo><title>iTunes Normalization settings</title><revhistory><revision><revnumber>3</revnumber><date>2013-11-25 01:22:45</date><authorinitials>DanONeill</authorinitials></revision><revision><revnumber>2</revnumber><date>2012-10-08 22:15:40</date><authorinitials>localhost</authorinitials><revremark>converted to 1.6 markup</revremark></revision><revision><revnumber>1</revnumber><date>2007-09-19 13:53:44</date><authorinitials>brixeng.brixnet.com</authorinitials></revision></revhistory></articleinfo><section><title>COMM - iTunes Normalization Settings (class 3)</title><para>iTunes writes a standard comment with a description of iTunNORM.  This contains the normalization information it uses.  A sample is: </para><itemizedlist><listitem override="none"><para><code>00001E86 00001E86 0000A2A3 0000A2A3 000006A6 000006A6 000078FA 000078FA 00000211 00000211</code> </para></listitem></itemizedlist><para>Discussions on the values: </para><itemizedlist><listitem><para><ulink url="http://robinbowes.com/projects/flac2mp3/ticket/30"/> </para></listitem><listitem><para><ulink url="http://www.hydrogenaudio.org/forums/index.php?showtopic=24620"/> </para></listitem><listitem><para><ulink url="http://svn.slimdevices.com/trunk/server/Slim/Utils/SoundCheck.pm?rev=10330&amp;view=markup"/> which says:</para><screen><![CDATA[The iTunNORM tag consists of 5 value pairs. These 10 values are encoded as
ASCII Hex values of 8 characters each inside the tag (plus a space as prefix).
 
The tag can be found in MP3, AIFF, AAC and Apple Lossless files.
 
The relevant information is what is encoded in these 5 value pairs. The first
value of each pair is for the left audio channel, the second value of each
pair is for the right channel.
 
0/1: Volume adjustment in milliWatt/dBm
2/3: Same as 0/1, but not based on 1/1000 Watt but 1/2500 Watt
4/5: Not sure, but always the same values for songs that only differs in volume - so maybe some statistical values.
6/7: The peak value (maximum sample) as absolute (positive) value; therefore up to 32768 (for songs using 16-Bit samples).
8/9: Not sure, same as for 4/5: same values for songs that only differs in volume.
iTunes is choosing the maximum value of the both first pairs (of the first 4 values) to adjust the whole song.]]></screen></listitem></itemizedlist></section></article>