Avocent DSView 3, Installer/User Manual

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Chapter 6: Using the Video Viewer 215
Image capture width, pixel sampling/fine adjust, image capture horizontal position
and image capture vertical position
The Image Capture Width, Pixel Sampling/Fine Adjust, Image Capture Horizontal Position and
Image Capture Vertical Position adjustments affect how the target video is captured and digitized
and are seldom changed.
The image capture parameters are automatically changed by the Automatic Adjustment function. A
special image is required on the target in order to make accurate adjustments independently.
Contrast and brightness
If the image in the Video Viewer window is too dark or too light, select Tools - Automatic Video
Adjust or click the Automatic Video Adjust button . This command is also available in the Video
Adjustments dialog box. In most cases, this will correct video problems. In those cases where
clicking on Auto Adjust several times does not set the contrast and brightness as desired, adjusting
the contrast and brightness manually may help.
First, increase the brightness. Do not go more than 10 increments before moving the contrast.
Generally, the contrast should be moved very little.
Detection thresholds
In some cases, noise in the video transmission keeps the packets/sec count up. This may be seen
when little dots change in the area of the cursor when it is moved. Varying the threshold values
may result in “quieter” screens and improved cursor tracking.
Noise Threshold and Priority Threshold values may be modified if you are using standard video
compression. Block Noise Threshold and Pixel Noise Threshold values may be modified if you are
using the DS1800 digital switch or DSR switch DVC algorithm upgrade. Default threshold values
can be restored by clicking
Auto Adjust Video .
Block noise threshold and pixel noise threshold
The Block Noise Threshold and Pixel Noise Threshold values set the minimum color levels in
terms of changed video blocks and pixels per thousand that are allowed.
• The Block Noise Threshold sets the minimum color change that will occur in a single video
block. Increasing the value will reduce the network bandwidth. Decreasing the value will make
the size of these artifacts smaller.
• The Pixel Noise Threshold sets the minimum color change in a single pixel. Decreasing the
value will reduce the number of low-contrast artifacts, but will increase network bandwidth.
F Brightness M Performance Monitor
G Block Noise Threshold N Close button
Table 6.2: Manual Video Adjust Dialog Box Descriptions (Continued)