Extron Electronics VN-Matrix 200 Series - Manual (Page 74)

Temporal compression setting
Temporal compression may be applied by selecting the Temporal check box. By default, this
option should always be selected.
Temporal compression causes data to be transferred only when a change occurs between
frames.
Quality Control settings
The Threshold setting modifies the detection point of the temporal compression algorithm.
A value of 0 results in all changes between frames being sent.
As the threshold value is increased, only changes above a certain level are sent, thus reducing
the bit rate. This control is used to compensate for image sources that have a level of noise
in them. In general, there is always a certain amount of noise in any source that is produced
by an analog method. By applying a threshold, this noise can effectively be ignored by the
PURE3 compression engine, resulting in a lower transmitted bit rate.
• 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 a value greater than 0.
• 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.
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 thresholds can increase the transmit bandwidth by up to 20%
so it should be disabled on bandwidth sensitive systems. It is usually not required on
video/camera type sources.
RefreshRate 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.
VN-Matrix 200 Series • Advanced Setup Procedures 69