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