VCS VIP 1000, Руководство пользователя

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Chapter 6 Configuring the Transmitter
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3 corresponds to 5MBPS low delay
5 MBit/s transmission rate with low image refresh delay
]
4 corresponds to 2MBPS high quality
2 MBit/s transmission rate with high image quality
]
5 corresponds to 3.5MBPS high quality
3.5 MBit/s transmission rate with high image quality
]
6 corresponds to 5MBPS high quality
5 MBit/s transmission rate with high image quality
]
7 corresponds to 2MBPS with audio
2 MBit/s transmission rate with additional audio transmission
]
8 corresponds to 3.5MBPS with audio
3.5 MBit/s transmission rate with additional audio transmission
Data rate:
The data rate for the speed of transmission over the network is shown for each
parameter value. You can change the data rate and decide whether you prefer a
constant data rate or consistent image quality.
Selecting constant means that the data will always be transmitted at the set rate,
but the image quality may vary. Selecting variable means that the image quality
will be consistent, but the data rate can vary from the set value.
GOP structure:
In MPEG-2 encoding, image sequences are divided into groups (GOP – G roup
o f P ictures). Each GOP can contain three different frame types. I-frames contain
the complete information for an image and thus require the most coding data. P-
frames code only the difference between the current image and the previous one.
These require considerably less data. Lastly, B-frames encode only the
difference between the current image and the previous and next images. The
require the least data. However, B-frames have a large delay, because image
information from subsequent images is required for encoding. Each GOP always
begins with an I-frame.
Note
B-Frames have a large delay and are not suitable for some applications,
such as manually controlling a dome camera. Keep this in mind when
choosing a GOP structure and length.