User`s manual

61
General performance considerations
Optimizing your system
To see the bandwidth and frame rate currently required by the video stream, the
AXIS 216FD/FD-V/MFD/MFD-V provides a tool that
can be used to display these values
directly in the video image.
To do this, special format strings are added as part
of
a text overlay. Simply add #r (average frame
rate in fps) and/or #b (average bandwidth in kbps)
to the overlay.
For detailed instructions, please see the online help
for Video
& Image > Text Overlay Settings, and
the help for File Naming & Date/Time Formats.
Important!
The figures displayed here are the values as delivered by the camera. If other restrictions are currently in
force, (such as bandwidth limitation), these values might not correspond to those actually received by the
client.
For Motion JPEG, these values would be accurate as long as no frame rate limit has been specified.
Bandwidth
As there are many factors that affect bandwidth, it is very difficult to predict the required
amounts. The settings that affect bandwidth are:
• image resolution
• image compression
•frame rate
• MPEG-4 GOV settings
• bit rate control settings
There are also factors in the monitored scene that will affect the bandwidth. These are:
• amount of motion
• image complexity
• lighting conditions
For MPEG-4, if there is only limited bandwidth avai
lable, and if this is more important
than the image quality, using a constant bit rate (CBR) is recommended. Use a variable bit
rate (VBR) if the image quality needs to be maintained at a higher level. If supported on the
network, consider also using MPEG-4 multicasting, as the bandwidth consumption will be
much lower.