Windows Media DRM Version 1	Windows Media DRM Version 7.x and 9	Windows Media DRM 10
Release Schedule	April 1999	January 2003	2004
Operating Systems	Windows 95, Windows 98, Windows NT 4.0, Windows 2000, Windows Millennium Edition, Windows XP, and Mac OS 8.1	Windows 98, Windows 2000, Windows Millennium Edition, and Windows XP	Windows XP, and non-Windows–based portable and network devices
Portable Device Support	Supports SDMI devices, non-SDMI devices, and portable media	Supports SDMI devices, non-SDMI devices, and portable media	Portable audio players, mobile phones, set-top boxes, and DVD players that support Windows Media DRM playback
Codecs	Windows Media Audio 1, 2, and 7, Windows Media Video 7, Microsoft MPEG-4 version 1 through 3, ISO MPEG-4 version 1, ACELP, Voxware, ATRAC-3	Windows Media Audio 1, 2, 7, 8, 9, 9 Professional, and 9 Voice, Windows Media Video 7, 8, 9 and 9 Image, Microsoft MPEG-4 version 1 through 3, ISO MPEG-4 version 1, and Windows Media Screen 7 Only DMO codecs supported for added security.	Windows Media Audio 1, 2, 7, 8, 9, 9 Professional, and 9 Voice, Windows Media Video 7, 8, 9 and 9 Image, Microsoft MPEG-4 version 1 through 3, ISO MPEG-4 version 1, and Windows Media Screen 7
Business Rules	Expiration date Unlimited play Transfer to SDMI/non-SDMI Burn to CD	Same, plus: Expiration date Unlimited play Transfer to SDMI/non-SDMI Burn to CD Start time End time Duration Counted operations (plays, transfers) * Supported on PCs	Same, plus: Expiration date Unlimited play Burn to CD Start time End time Duration Counted operations (plays, transfers) *All but the burn to CD scenario are supported on portable devices
User Experience	Silent licensing and pre-delivery of licenses are not supported . Users are very aware of the extra steps that they have to go through.	Silent licensing Pre-delivery of licenses Backup and restore of licenses Modal dialogs within players License management	Greater device functionality Subscription content transfer to devices Faster license acquisition and renewal Playback of protected content on network devices
Security	Encryption of content and license	Encryption of content and license, plus: Individualization Secure Audio Path (Windows Millennium Edition and Windows XP) Revocation of player application Revocation of content (version 7.1 and later) Exclusion of player application (version 7.1 and later) Exclusion of Protected Content Module (version 7.1 and later)	Same, plus revocation and exclusion are extended to portable devices and network devices.