There are no requirements on max storage size supported.  However, we do have a requirement of supporting up to 50,000 songs.
 

For audio file formats, the following extensions are supported:

 

• wma

• .m4a, .m4b
• mp3
• .wav
• .aac,.aa, .aax
• .flac
• .ogg
• .ape
• .aiff, .aif,
• .dsf