Media redirection in XenApp/XenDesktop with HDX (SpeedScreen)

Media playback within a XenApp or XenDesktop session has always been a challenge when designing a server based computing solution. The user’s experience is degraded through choppy playback and the host server is taxed processing the audio and video playback. Administrators have typically addressed this challenge by educating users to leverage their local client browser and media player whenever media functions were required. Not only does this introduce obvious training challenges in educating users, the experience is less than ideal having users switch between the “server” and “client” environments. Not to mention any new application integration issues that this generates.

Over the last few years Citrix has made incremental improvements to its HDX (formerly called SpeedScreen) technology to improve Flash and general media to solve this challenge. The improvements are significant over RDP, but playback overall is still not even close to “local” speed. Along with traditional improvements to HDX, Citrix has quietly included media redirection in XenApp and XenDesktop for certain media types. This is the mechanism in which media playback is offloaded to the client workstation for a more seamless experience. The server passes instructions to play the media to the client and the local audio and video codec is used for the actual playback. Media plays back seamless and the server processor is not taxed in the process. At the moment, XenApp and XenDesktop support DivX, XVid, MP3, among other media types. Check out this Citrix technote on all of currently supported media. From an administrator’s perspective, the requirements to enable this functionality are very straight forward. Enable SpeedScreen and ensure the client and server have codec installed and it will just work (given that the media type is supported).

As of last month, Citrix released a trial to enable Flash redirection (currently not officially supported). Flash has become the de facto standard for streaming video and multimedia on the internet, so the full release will be highly anticipated (tentative for Q3). Not that most users are doing this, but to test the technology, I was able to play back a 720p video through a XenApp server without any skipping or lag. Impressive stuff.