7 Appendix
7.1 Terms
Dual-stream
Dual-stream: one high bit rate stream for the local HD store, QCIF/CIF/2CIF/DCIF/4CIF coding, other
low bit rate stream for network transmission, such as QCIF / CIF coding,
I Frame
I frame: intra frame image, remove redundant information to compress the transmittal data, also called key
frames.
B Frame
B frame: According to time redundant of the source image sequence previously encoded frame and account
the source image after the encoded frame to compress transmittal data, also known as bi-directional
prediction frame.
P Frame
P-frame: according to image frame lower than the previous ’time redundant to compress transmittal data,
also called predicted frames.
Wide Dynamic
Bright parts and dark parts in particular can be seen very clearly at the same time. Wide dynamic range is a
ratio between the brightest luminance signal value and the darkest value.
S
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M
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A
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R
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T
SMART (Self Monitoring, Analysis and Reporting Technology): now widely used in hard disk data
security technology, monitoring system analysis Motor, circuit, HDD and disk head when HDD working,
warn when abnormality, sometimes will automatically slow down and back up data.
CVBS
Composite Video Broadcast Signal, consists of luminance and color signal from the composite baseband
signal.
BNC
Coaxial cable connector, composite video signals or audio signals, commonly use 75 ohm connectors.
BNC welding and should pay attention to weld strength and remove burrs, or the signal wire and shield’s
contact will lead to a substantial attenuation of signal strength
7.2 HDD Capacity Calculation
7.2.1 Reference of HDD Capacity Calculation
The first time install DVR, please check if the HDD has installed.
The capacity of the HDD
There is no limitation of capacity of single HDD to DVR, please choose the HDD according to the videos’
saving time.
The choose of the Capacity
Computational formula of HDD Capacity:
Whole HDD Capacity = number of the channels × time in need (hour) × spent of HDD Capacity per hour
