Appendix A Hdd Capacity Calculation - Dahua NVR4108-P User Manual

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Appendix A HDD Capacity Calculation

Calculate total capacity needed by each device according to video recording (video recording type and
video file storage time).
Step 1: According to Formula (1) to calculate storage capacity
needed for each hour, unit Mbyte.
Step 2: After video time requirement is confirmed, according to Formula (2) to calculate the storage
m
capacity , which is storage of each channel needed unit Mbyte.
i
Step 3: According to Formula (3) to calculate total capacity (accumulation)
channels in the device during scheduled video recording.
Step 4: According to Formula (4) to calculate total capacity (accumulation)
channels in device during alarm video recording (including motion detection).
q
i
d
In the formula: means the bit rate, unit Kbit/s
i
m
In the formula:
h
means the recording time for each day (hour)
i
D
means number of days for which the video shall be kept
i
c
In the formula: means total number of channels in one device
In the formula：a% means alarm occurrence rate
q
that is the capacity of each channel
i
   
d 8 3600 1024
i
q h D
= × ×
i i i i
c


q m
T i

i 1
c


q m
×a%
T i

i 1
q
that is needed for all
T
q
that is needed for all
T
286
(1)
(2)
(3)
(4)