In order to prevent users from copying DRM content, Windows Vista provides process isolation and continually monitors what kernel-mode software is loaded.
Some output types such as S/PDIF (Sony/Philips Digital Interchange Format) typically don't have a suitable DRM scheme available, so these need to be turned off reliably if the content so specifies.
However, rather than being a software application programming interface, PVP-OPM operates with the Windows media components in the protected environment.
In January 2007 the developer Alex Ionescu announced that he had found a method that allows end users to bypass Vista's Protected Media Path.
This would allow digital content to be played on equipment that does not implement DRM restriction measures (like rescaling of video resolutions and disabling analog audio outputs).
[7] Microsoft has frequently been accused of adding the Protected Media Path feature to Vista to block customers from copying rightfully owned media content[8] (a practice believed to be protected by Fair Use provisions of the Copyright Act), and the feature is widely quoted as an example of Microsoft's uncompromising adherence to DRM.