what type of audio file does itunes use
iTunes iTunes keeps track of songs by creating a virtual library, allowing users to access and edit a song's attributes. These attributes, known as metadata, are stored in a binary library file called iTunes Library, which uses a proprietary file format ("ITL"). It caches information like artist and genre from the audio format's tag capabilities (the ID3 tag, for example) and stores iTunes-specific information like play count and rating. iTunes typically reads library data only from this file.[27] A second file can also be created if users activate a preference; the iTunes Music Library.xml file is refreshed whenever information in iTunes is changed. It uses an XML format, allowing third-party apps to access the library information (including play count, last played date, and rating, which are not standard fields in the ID3v2.3 format). Apple's own iDVD, iMovie, and iPhoto applications all access the library.[28] If the first file exists but is corrupted, such as by making it zero-length, iTunes will attempt to reconstruct it from the XML file. Detailed third-party instructions regarding this can be found elsewhere.[29] Beginning with iTunes 10.5.3 this behavior has been changed such that the XML file is not read automatically to recreate the database when the database is corrupted. Rather, the user should load the iTunes Library.xml file via File > Library > Import Playlist....