Product Documentation

Thinwire Compatibility Mode

Oct 06, 2015

Thinwire Compatibility Mode uses new screen decomposition and caching techniques, which achieve low bandwidth usage and high server scalability without compromising the end-user experience.

Thinwire Compatibility Mode includes the following features:

  • Intelligent bitmap matching for a bitmap-only provider.
    • Bitmap translation analysis for efficient window movement and scrolling.
  • Backwards compatible. There is no requirement for client or Citrix Receiver upgrades or hardware acceleration.
    • Tested on a range of older thin clients up to and over 5 years old.
  • Optimized for very low server CPU usage and improved server scalability.
  • An emulated 16-bit mode, which reduces bandwidth by a further 15-20% for typical workloads.
  • Transient detection for server-rendered video content.
    • Multi-transient handling for an improved multimedia experience. For example, when watching multiple videos or ticker tapes.
    • Selective sharpening for regions that leave a transient state.
  • Optimized for CloudBridge acceleration. In tests, we have seen up to a 6:1 ratio of bandwidth reduction on Office-type workloads.
  • Adaptive display, which can be tuned through policy settings. For more information see Moving image compression in Moving image policy settings.
  • VDA's and Windows OS's up to and including Windows 10 VDA are supported.
  • New "Build to Lossless" mode for 3D Pro, which improves responsiveness, interactivity, and interruptible sharpening for a better user experience on low bandwidth.
  • Default static photographic imagery quality is higher than in Legacy Graphics Mode. 

For Visual Quality settings "Low", "Medium" (default) and "High", the transient detector dynamically evaluates screen updates to decide whether highly-animated areas should be sent at lower quality, in accordance with the Adaptive Display policy, to improve client performance and reduce bandwidth usage.

For the Build to lossless visual quality, Thinwire Compatibility Mode uses a "fuzzy-first" approach for large screen updates. This setting is targeted at 3D Pro users who are manipulating 3D models or other graphic-intensive applications. If the activity continues, a transient mode is assumed and the affected area is sharpened and cached once transient activity stops. For the initial large change, some lightweight image analysis is performed on the change area to determine whether to use "fuzzy transient" or "sharp transient" (lossless) - for example, when rotating a wireframe. It is more efficient, for FPS (Frames Per Second) and bandwidth, to encode simple imagery using the Citrix lossless codec and no loss in quality occurs.

The sharpen-to-lossless step in Build to lossless is also different. Rather than sharpening the affected area in one step, the area is sharpened in pre-determined blocks to help maintain interactivity and a smooth user experience. Sharpening a large change area mid-transient, for example moving a 3D model which is stopped briefly, then moved again, would previously cause a "stall", especially over a low bandwidth line. The size of the sharpening blocks depends on how far the quality was reduced to try and maintain the target minimum frame rate, which is an Adaptive Display policy setting. If the quality was significantly reduced, the sharpening block size will be smaller, with a minimum size of 128 x 128 pixels. If the quality was not reduced, for example, when the client has adequate processing power and bandwidth, the sharpening block size can be a maximum size of 384 x 384 pixels.