Vivotek FD9167-H User Manual page 83

Bit rate control
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Constrained bit rate:
A complex scene generally produces a larger file size, meaning that higher bandwidth
will be needed for data transmission. The bandwidth utilization is configurable to
match a selected level, resulting in mutable video quality performance. The bit rates
are selectable at the following rates: 20Kbps, 30Kbps, 40Kbps, 50Kbps, 64Kbps,
128Kbps, 256Kbps, 512Kbps, 768Kbps, 1Mbps, 2Mbps, 3Mbps, 4Mbps, 6Mbps,
8Mbps, 10Mbps, 12Mbps, 14Mbps, ~ to 40Mbps. You can also select Customize
and manually enter a value up to 40Mbps.
• - Target quality: Select a desired quality ranging from Medium to Excellent.
- Maximum bit rate: select a bit rate from the pull-down menu. The bit rate ranges
from 20kbps to a maximum of 40Mbps. The bit rate then becomes the Average or
Upper bound bit rate number. The Network Camera will strive to deliver video streams
around or within the bit rate limitation you impose.
- Policy: If Frame Rate Priority is selected, the Network Camera will try to maintain
the frame rate per second performance, while the image quality will be compromised.
If Image quality priority is selected, the Network Camera may drop some video
frames in order to maintain image quality.
Smart Q: Select ON or OFF to enable or disable the feature. Smart Q is scene-aware.
The Smart Q reduces frame size and bit rate consumption through the following:
Dynamically adjusting the image quality for scenes in different luminosities, and
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hence reduces the occurrence of noises in low light frames. Less noises means
less of the bandwidth consumed.
Endorsing different qualities for the I frames and P frames, and hence reduces
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the frame size. The higher the quality of the I frame, the larger the GOP (Group
of Pictures). More block skips will occur and more P frames will be included in the
GOP, and therefore the bit rate consumption is reduced.
■ Dividing a single frame into different sections, and giving these sections different
quality values. For example, a highly complex image section (high frequency
area), such as an area with dense vegetation, screen windows, or repeated
patterns (wall paper), can be given a lower quality value. For a highly complex
area, having a lower quality value actually poses little effects on human eyes.
High quality is unnecessary in no motion area, especially in low light, high noises,
and high frequency scenes. Unnecessary quality is unrecognized by human eyes
and wastes the bit rate. The quality areas in a scene are determined by the SoC
encoder.
The Smart Q streaming can save up to 50% to 80% of bandwidth in different
illumination conditions while keeping the same imaging quality. These numbers come
from the comparision between Smart Stream II and Smart Stream III streamings.
VIVOTEK
User's Manual - 83