XenApp and XenDesktop provide a superior graphics and video experience for most users by default, with no configuration required.
By default, XenDesktop deliver a highly responsive Windows Aero or Windows 8 desktop experience to virtual desktops accessed from Windows user devices. To do that, XenDesktop leverage the graphics processing unit (GPU) or integrated graphics processor (IGP) on supported Windows user devices for local DirectX graphics rendering. This feature, referred to as desktop composition redirection, maintains high scalability on the server.
For detailed information, see What to do with all these choices in http://blogs.citrix.com/2013/11/06/go-supersonic-with-xendesktop-7-x-bandwidth-supercodecs/#Choices.
Users of the latest Citrix Receiver releases will notice improved performance for server-rendered video.
To reduce the bandwidth required in user sessions, consider adjustments to the following policy settings. Keep in mind that adjustments to these settings can reduce the quality of the user experience.
|Windows Aero preview option||Description|
|Taskbar Preview||When the user hovers over a window's taskbar icon, an image of that window appears above the taskbar.|
|Windows Peek||When the user hovers over a taskbar preview image, a full-sized image of the window appears on the screen.|
|Flip||When the user presses ALT+TAB, small preview icons are shown for each open window.|
|Flip 3D||When the user presses TAB+Windows logo key, large images of the open windows cascade across the screen.|
To reduce bandwidth requirements, disable this policy setting.
If user devices, such as thin clients, have slow CPUs, specify a lower value to improve the user experience.
If server scalability is an issue, specify a lower value. If server CPU utilization stays at or near 100%, consider adding an additional vCPU.
(color depth in bits per pixel / 8) * (vertical resolution in pixels) * (horizontal resolution in pixels) = memory required in bytes
For example, if the color depth is 32, the vertical resolution is 600, and the horizontal resolution is 800, then the maximum memory required is (32 bpp / 8) * (600 pixels) * (800 pixels) = 1920000 bytes, so you would set the Display memory limit to 1920 KB.
Color depths other than 32-bit are available only if the Legacy graphics mode policy is enabled.
To improve bandwidth efficiency and latency tolerance during video conferencing in a session, HDX webcam video compression is used for webcams by default. HDX webcam video compression streams webcam traffic over a dedicated multimedia virtual channel. HDX webcam video compression uses significantly less bandwidth compared to the isochronous HDX Plug-n-Play support and works well over WAN connections.
However, Receiver users can override the default behavior by choosing the Desktop Viewer Mic & Webcam setting Don't use my microphone or webcam. To prevent users from switching from HDX webcam video compression, disable USB device redirection through the policy settings under ICA > USB Devices.
HDX webcam video compression requires that the following policy settings are enabled. All of these settings are enabled by default.
To force software compression over low bandwidth networks
If a webcam supports H.264 hardware encoding, HDX video compression uses the hardware encoding by default. Hardware encoding uses additional bandwidth and is not suitable for a low bandwidth network.
To force software compression, add the following DWORD key value to the registry key HKCU\Software\Citrix\HdxRealTime: DeepCompress_ForceSWEncode=1.
For deployments where server scalability is of greater concern than user experience, you can use the legacy graphics system by adding the Legacy graphics mode setting to a policy and configuring the individual legacy graphics policy settings. Use of the legacy graphics system particularly impacts the user experience over WAN and mobile connections.