Vivotek IP7138 - Manual (Page 22)

For Best Real-time Video Images
To achieve good real-time visual effect, the network bandwidth should be large enough
to allow a transmission rate of greater than 20 image frames per second. If the
broadband network is over 1 Mbps, set the “Fix bit rate” to 1000Kbps or 1200Kbps, or
set “Fix quality” at the highest quality. The maximum frame rate is 30. If your network
bandwidth is more than 512Kbps, you can fix the bit rate according to your bandwidth
and set the maximum frame rate to 30 fps. If the images vary dramatically in your
environment, you may want to slow the maximum frame rate down to 20 fps in order
to lower the rate of data transmission. This allows for better video quality and the
human eyes cannot readily detect the differences between those of 20, 25, or 30
frames per second. If your network bandwidth is below 512 Kbps, set the “Fix bit rate”
according to your bandwidth and try to get the best performance by fine-tuning with
the “Maximum frame rate”. In a slow network, greater frame rate results in blur images.
Video quality performance will vary somewhat due to the number of users viewing on
the network; even when the parameters have initially been finely tuned. Performance
will also suffer due to poor connectivity because of the network’s burst constraint.
Only Quality Images Will Do
To have the best video quality, you should set “Fix quality” at “Detailed” or “Excellent”
and adjust the “Maximum frame rate” to match your network’s bandwidth. If your
network is slow and you receive “broken” pictures, go to the TCP or HTTP protocol in
“MPEG-4 Protocol Options” and choose a more appropriate mode of transmission. The
images may suffer a time delay due to a slower connection. The delay will also increase
with added number of users.
Somewhere Between Real-time and Clear Images
If you have a broadband network, set “Fix quality” at ”Normal” or better, rather than
setting “Fix bit rate”. You can also fix the bandwidth according to your actual network
speed and adjust the frame rate. Start from 30 fps down for best results but not below
15 fps. If the image qualities are not improved, select a lower bandwidth setting.
21 - User's Manual
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