Cisco 8620, Справочное руководство

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Cisco Video Surveillance 8620/8630 IP Camera Reference Guide
Chapter 5 Configuration
Media > Video
When completed with the settings in the Viewing Window, click Save to enable the settings and click
Close to exit the window. The selected Output Frame Size will immediately be applied to the Frame
size of each video stream. Then you can go back to the home page to test the digital PTZ function.
For more information about the digital PTZ function, see the
“PTZ > PTZ settings” section on
page 5-35 .
Click the stream item to display the detailed information. The maximum frame size will follow your
settings in the above Viewing Window sections.
This camera offers real-time H.265, H.264, and MJPEG compression standards (Triple Codec) for
real-time viewing. If the H.264 or H.265 mode is selected, the video is streamed via the RTSP protocol.
There are several parameters through which you can adjust the video performance:
• Frame size—You can set up different video resolutions 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, or recording the stream to an NVR. A
larger frame size takes up more bandwidth.
•
Maximum frame rate—Limits the maximum refresh frame rate per second. Configure the frame rate
higher for smoother video viewing and for recognizing moving objects in the field of view. If the
power line frequency is set to 50Hz, the frame rates are selectable at 1fps, 2fps, 3fps, 5fps, 8fps,
10fps, 12fps, 15fps, and up to 50fps. If the power line frequency is set to 60Hz, the frame rates are
selectable at 1fps, 2fps, 3fps, 5fps, 8fps, 10fps, 12fps, 15fps, and up to 60fps. You can also select
Customize and manually enter a value.
The frame rate will decrease if you select a higher resolution.
•
Intra frame period—Determine how often for firmware to plant an I frame. The shorter the duration,
the more likely you will get better video quality, but at the cost of higher network bandwidth
consumption. Select the intra frame period from the following durations: 1/4 second, 1/2 second, 1
second, 2 seconds, 3 seconds, and 4 seconds.
• Smart Stream III
–
Dynamic Intra frame period—High quality motion codecs, such as H.265, utilize the
redundancies between video frames to deliver video streams at a balance of quality and bit rate.
The encoding parameters are summarized and illustrated in Figure 5-3 . The I-frames are
completely self-referential and they are largest in size. The P-frames are predicted frames. The
encoder refers to the previous I- or P-frames for redundant image information.
Figure 5-3 H.264/H.265 Frame Types
By dynamically prolonging the intervals for I-frames insertion to up to 10 seconds, the bit rates
required for streaming a video can be tremendously reduced. When streaming a video of a static
scene, the Dynamic Intra frame feature can save up to 53% of bandwidth. The amount of
bandwidth thus saved is also determined by the activities in the field of view. If activities occur