VIVOTEK
User's Manual - 83
■
Bit rate control
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 adjustin
g the image quality for scenes in different luminosities 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
the frame size.
■ Dividing a sin
gle frame into different sections, and giving these sections different
qualities. For a highly complex area, such as an area with dense vegetation,
screen windows, or repeated patterns (complex textiles patterns like wall paper),
having a lower quality value actually poses little effects on human eyes.
Unnecessary quality is unrecognized by human eyes and wastes the bit rate.
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 comparison between Smart Stream II and Smart Stream III streamings.
