User`s manual

Moxa VPort 26A-1MP System Configuration
4-32
Video Quality Control
Video Quality Control is used to optimize the bandwidth of the MPEG4 video stream. There are 2 modes for
video quality control.
Setting Description Default
Fixed bit rate
(Only for H.264)
The administrator can fix the bandwidth to tune the video
quality and FPS (frames per second) to the optimum
combination.
The VPort will tune the video performance according to the
configured bandwidth. A higher bandwidth means better
quality and higher FPS.
4000Kbps in
1280x720 resolution
Fixed Quality The administrator can set the image quality to one of 5
standards: Medium, Standard, Good, Detailed, or
Excellent. The VPort will tune the bandwidth and FPS
automatically to the optimum combination.
Good
CBR Pro™
General CBR (constant bit rate) configuration limits throughput to 1 second, but since video streaming is
designed to transmit immediately to shorten latency time, network throughput may experience a burst in
action during short time periods, in which case packet loss will occur if the network bandwidth buffer is not
large enough. When packet loss occurs, images will show a mosaic effect. For this reason, the VPort 26A-1MP
supports an advanced CBR Pro™ function, which can enable the flow control of image packets to ensure no
packet loss for limited bandwidth transmissions, such as on xDSL or wireless networks.
Image without packet loss Image with packet loss
Setting Description Default
Limits the maximum
throughput of each
connection in
 kbits
within
 milliseconds
Configure how much throughput is allowed on the network
within the given number of milliseconds. For example, if the
configuration is 20 kbits within 5 milliseconds, the
video packet
throughput will be limited to 20 kbits within 5 milliseconds.
20 kbits within 5
milliseconds.
NOTE
The image quality, FPS, and bandwidth are influenced significantly by network throughput, system network
bandwidth management, applications the VPort runs (such as VMD), how complicated the image is, and the
performance of your PC or notebook when displaying images. The administrator should take into consideration
all of these variables when designing the video over IP system, and when specifying the requirements for the
video system.
NOTE
Visit
http://www.moxa.com/event/Net/2012/IP_CCTV_Calculator/index.htm to get help for network
bandwidth estimation of different resolutions, FPS, video content, etc.