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Cisco Video Surveillance 8620/8630 IP Camera Reference Guide
Chapter 5 Configuration
Media > Video
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Policy—If Frame Rate Priority is selected, the 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 camera may drop some video frames in order to maintain image quality.
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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 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 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 comparison
between Smart Stream II and Smart Stream III streaming.
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Bit rate control—Fixed quality:
If Fixed quality is selected, all frames are transmitted with the same quality; bandwidth utilization
is therefore unpredictable.
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Quality— The video quality can be adjusted to the following settings: Medium, Standard, Good,
Detailed, and Excellent. You can also select Customize and manually enter a value.
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Maximum bit rate—With the guaranteed image quality, you might still want to place a bit rate
limitation to control the size of video streams for bandwidth and storage concerns. The
configurable bit rate starts from 1Mbps to 40Mbps.
The Maximum bit rate setting in the Fixed quality configuration can ensure a reasonable and limited
use of network bandwidth. For example, in low light conditions where a Fixed quality setting is
applied, video packet sizes can tremendously increase when noises are produced with electrical
gains.
If JPEG mode is selected, the camera sends consecutive JPEG images to the client, producing a
moving effect similar to a filmstrip. Every single JPEG image transmitted guarantees the same
image quality, which in turn comes at the expense of variable bandwidth usage. Because the media
contents are a combination of JPEG images, no audio data is transmitted to the client. There are three
parameters provided in MJPEG mode to control the video performance:
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Frame size—You can set up different video resolution for different viewing devices. For
example, set a smaller frame size and lower bit rate for remote viewing on mobile phones and
a larger video size and a higher bit rate for live viewing on web browsers. Note that a larger
frame size takes up more bandwidth.
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Maximum frame rate—Limits the maximum refresh frame rate per second. Set the frame rate
higher for smoother video quality. If the power line frequency is set to 50Hz (at the 5MP
resolution), the frame rates are selectable at 1fps, 2fps, 3fps, 5fps, 8fps, 10fps, and up to 25fps.
