Extron Electronics VN-Matrix 250 User Guide User Manual
Page 55
When the slider is set to unlimited, the bit rate depends on the complexity (detail and
motion) of the source image. As the slider is adjusted to reduce the maximum bit rate, the
encoder progressively drops frames in order to limit the instantaneous bit rate. The number
of frames dropped depends on the source image complexity.
NOTE: Extron advises against using more than 300 Mbps for most applications. Check
with your network administrator to determine the available bandwidth.
The
Video Quality slider adjusts the amount of spatial compression that is applied to the
source image. Video Quality is set in steps ranging from low to high quality.
The low setting (one star) provides the lowest
image quality (with the highest compression).
The high setting (four stars) provides the highest
image quality (with the lowest compression).
Either of two transform types can be selected using the transform drop‑down list:
z
Graphics
is optimized for text and sharp lines, as is present on most computer
screens.
z
Video
is optimized for smooth tone changes such as is present in movies and other
video content.
Monitoring the bit rate
The bit rate of the streamed image is monitored in the Streams information area of the
Bandwidth tab.
# Destination
Trans
BW(Mbps) Drop% RTT(us)
1 VND200_PDTEST.videowindow
0
0.0
Streams
rtp(m)
0.000
Figure 33.
Bandwidth Streams
The Streams list shows network statistics for current RTP streams. For each RTP stream,
three values are presented: the transmit bandwidth (Trans) (in megabits per second), the
packet drop percentage (Drop %) and the round trip delay time (RTT, in microseconds). The
transmit bandwidth is the true bandwidth of the source measured over the last second.
All of this data may not have arrived at the destination if the link shows packets are being
dropped. Most networks show a small amount of dropped traffic, but when this loss rate
rises above 5%, it indicates that the capacity of the link has probably been exceeded.
A lightly loaded network shows a fairly constant RTT. When this value starts to rise or
fluctuates excessively it indicates the network is congested. Usually when network capacity
has just been exceeded, the RTT rises to a large value just before packets start being
dropped. The link latency rises as RTT increases.
Video Quality
low
high
Video Quality
low
high
VNM 250 • VNM 250 GUI Overview
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