Zattoo is a proprietary peer-to-peer Internet Protocol Television system ("P2PTV") with current focus on European channels, licensed content, and Digital Rights Management. It is developed by researchers and programmers based out of Ann Arbor, with corporate offices in San Francisco and Zurich. As of December 2006, the product is in public beta testing. The player is based on H.264 (QuickTime and ffmpeg), and is Mac OS X, Linux, Windows 2000, Windows XP and Windows Vista compatible. It needs a minimum downstream bandwidth of 400 kbit/s on the client side.