More about "Fairplay" DRM

[Henri]

(from Gold Coast Macuser Group's mailing list)

This is a brief summary of Apple's Digital Rights Management System based on
available information. Please send in corrections or further
observations/experiences.

For the purposes of this article:


DRM = Digital Rights Management.
Protected AAC = AAC purchased from Apple's Music Store.

Apple introduced their new iTunes Music Store which features AAC formated
files available for download. The new files feature a form of "Digital
Rights Management"... aka Copy Protection. First word of Apple's work on
this technology with respect to MPEG4 (AAC) was in a PCPro.co.uk article in
February of this year. At that time, DRM incorporation into the MPEG4
standard was set to be accomplished by June of this year.

How it Works

Surprisingly few details about the implementation of the AAC DRM have been
revealed. The following represents a list of restrictions and capabilities
for consumers as gathered at this time:

- Protected AAC files have the extension: .m4p -- ripped AAC files are .m4a

- Unlimited CD Burning of Protected AACs

- Only the iPod and Apple's iTunes, and it seems Quicktime-based apps
currently allow playing of these Protected AAC's.

- Up to three computers (at one time) can be authorized to play Puchased
AAC's. Deauthorizing your computer and reauthorzing new computers is
relatively simple.

- Playlists containing any Protected AAC's can only be burned 10 times. You
must change the list manually before you can burn again. [ Tech Note ]

- Burning a Protected AAC to a CD strips all encoding and DRM. That CD can
then be used as any CD song is used. The quality of the song on the CD is
identical to the AAC version. However, then ripping the song into MP3 or AAC
will result in loss of some quality. While ripping a song into any lossy
compression format will result in loss of quality -- recompressing these
previously compressed songs may exaggerate the quality loss. Your results
will vary depending on the exact piece of audio. Anecdotal evidence suggests
re-ripping into AAC yields better quality than re-ripping into MP3.

- Transcoding from Protected AAC to MP3/AIFF from iTunes is prohibited by
iTunes.

- If you're listening to a shared library or playlist, iTunes skips any
purchased music in the list (if the computer is not authorized to play the
music). To listen to a purchased song in a shared library or playlist, you
need to double-click the song. If your computer is not authorized to play
songs purchased by the person who is sharing the song, you'll need to enter
that person's Apple Account ID and password to hear the song. [ Tech Note ]

- According to Apple: iTunes will only play AAC files that are created by
iTunes or downloaded from the Music Store. "Other AAC files that you find on
the Internet or elsewhere will not play in iTunes." However, Anecdotal
evidence does not support this. Users have reported being able to play AAC
files encoded outside of iTunes. [ Tech Note ]

- AACs you rip from CD yourself (via iTunes) have no restrictions.

- Authorization/Deauthorization appears to be based on a central server
model... as Apple claims that "Initializing the drive will not deauthorize
the computer. If you will be initializing the drive, deauthorize the
computer first, then initialize the drive." [ Tech Note ]

Other Tips

- If your music store download gets interrupted, iTunes should restart when
you reconnect. Tech Note
- Easily Adding Art to iTunes: MacOSXHints
- Sharing Music over IP: MacObserver