INST
ALLA
TION
3
CONFIGURA
TION
OPERA
TION
FUR
THER
INFORMA
TION
INDEX
ALIF FEATURES
AFZ lossless codec
The AFZ compression scheme is primarily focused on improving the performance for
“natural” images (i.e. photographs and movies) and is automatically selected whenever
there is a benefit to do so. The AFZ codec is lossless and is very low latency (a small
fraction of a frame delay). It generally achieves 50% improvement (in compression) over
the RLE scheme for any areas of the screen that consist of images, gradients, shadows
etc., elements commonly found in modern desktop environments.
To maintain compatibility with non AFZ -enabled transmitters and receivers there is an
automatic switching method which will revert back to RLE compression when an ALIF
(1000) receiver is connected to the newer ALIF 1002 series or ALIF dual (2000 series).
Magic Eye (anti-dither support added)
The Magic Eye feature increases performance and reduces network traffic when ALIF
units are used with Apple Macs and other host computers that have dithered video
output. It also improves performance if the video source is noisy (e.g. from a VGA-to-DVI
converter).
Dithering is a technique used by some graphics cards to improve perceived image quality
by continuously varying the color of each pixel slightly. This gives the illusion of more
shades of color than the display can really reproduce, and smooths the appearance of
gradually shaded areas in images. Unfortunately dithering is an issue for KVM extenders
such as ALIF because it makes the image appear to be changing all the time even when
it is static, thus creating much more network data than can be carried by a Gigabit
Ethernet. The result is a reduction in video frame rate, which the user sees as slow
mouse response.
Magic Eye works by ignoring small variations in the video from frame to frame. It is
enabled by default as it is not obvious to the user that his poor mouse behaviour is
caused by dithering. In most cases Magic Eye is invisible, but it can produce slight color
inaccuracies on the monitor. For full color accuracy, Magic Eye can be disabled (within the
transmitter video configuration page
) for video sources which are not dithered or noisy.
Transport Layer Security (TLS)
ALIF 1002 and ALIF dual units support the industry standard Transport Layer Security
(TLS) protocol. This offers protection against eavesdropping and tampering by third
parties when data are transferred between ALIF transmitters and receivers across
networks (and also between ALIF units and AIM servers).
New feature: AFZ+ codec
AFZ+ compliments the existing AFZ codec by providing greater compression for
increased speed where pixel perfect results are not the primary focus. The
transmitter
video configuration page
allows you to choose the required compression mode. Choices
are:
• ‘
Pixel perfect
’ - only uses pixel perfect AFZ,
• ‘
Adaptive
’ - guarantees frame rate, builds to pixel perfect,
• ‘
Smoothest video
’ - forces the maximum compression, or
• ‘
Advanced
’ - allows you to choose the mode:
• ‘
AFZ only (pixel perfect),
• ‘
AFZ+ Minimum compression’
,
• ‘
AFZ+ Middle compression’
, or
• ‘
AFZ+ Maximum compression’
.