Extron Electronics VN-MATRIX User Guide - Manual (Page 71)

VN-MATRIX User Guide Section 4: Advanced Setup Procedures
I458GB issue 6 Page 71
Compression Settings
The Luminance and Chrominance settings can be individually modified
(Lock unchecked) or they can be locked together (Lock checked).
When locked together the Chrominance tracks the Luminance setting plus 2 stops.
The Luminance compression can be modified between 0 and 10, where 0 is no compression and 10
is maximum compression. The picture may look noticeably ‘blocky’ at higher compression values. A
value of 4 is a good compromise for efficiency and visual integrity.
The Chrominance compression can be modified between 0 and 11, where 0 is no compression and
11 is maximum compression. Excess screen artifacts will become visible if the chrominance
compression is set more than two points above the luminance setting. A value of 6 is a good
compromise for efficiency and visual integrity.
Quality Control Settings
These settings control the dynamic
nature of the compression system -
how the system responds to
changes in the source input.
Choose the preset option that best matches the type of imagery and
the type of compression to be applied or choose Advanced and adjust
the settings as follows:
Temporal compression causes areas of the screen to be refreshed only when a change between
frames is detected. Enabling temporal compression can significantly reduce network bandwidth. It it
best used with the screen refresh capability. For all normal operation it is suggested that temporal
compression is enabled.
Threshold controls the sensitivity of the temporal change detection algorithm. A value of 0 means any
screen changes will be sent. Increasing the value increases the send threshold and reduces the
network bandwidth. A setting of 0 is suitable for DVI computer generated sources. Sources with more
noise or video-type motion should use a setting between 1 and 4. Camera sources should always use
value greater than 0.
Chroma controls whether the temporal algorithm should consider changes in the color or
chrominance of the image. Enabling Chroma gives better results on digital simulation type sources,
however Chroma thresholding can increase the transmit bandwidth by up to 200% so it should be
disabled on bandwidth sensitive systems. It is usually not required on video/camera type sources.
Refresh Rate controls how frequently the non-changing parts of the screen are updated in temporal
compression mode. This is useful when connecting new displays to a temporally encoded source and
to fill in gaps in the data when using a lossy network transport such as RTP. A value of 1 refreshes
the screen in one second, a value of 0.1 refreshes the screen 10 times per second. A value of 0
disables the refresh.
The compression system supports two Transform types:
• Graphics is optimised for text and sharp lines, such as is present on most computer screens.
• Video is optimised for smooth tone changes such as is present in movies and other video
content.
Motion compression can be modified between 0 and 15, where 0 is no additional motion compression
and 15 is full motion compression. When enabled, where motion is detected on the screen that area is
compressed more heavily. This reduces bandwidth at a time when the eye cannot perceive significant
detail. When the motion stops the screen area is resent at the standard resolution preserving the
screen integrity.