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Appendix A
HDD Capacity Calculation
Calculate total capacity needed by each DVR (WITHOUT HDD) according to video recording (video
recording type and video file storage time).
Step 1: According to Formula (1) to calculate storage capacity
i
q
that is the capacity of each channel
needed for each hour, unit Mbyte.
1024
3600
8
=
i
i
d
q
(1)
In the formula:
i
d
means the bit rate, unit Kbit/s
Step 2: After video time requirement is confirmed, according to Formula (2) to calculate the storage
capacity
i
m
, which is storage of each channel needed unit Mbyte.
=
×
i
h
×
i
D
(2)
In the formula:
Means the recording time for each day (hour)
Means number of days for which the video shall be kept
Step 3: According to Formula (3) to calculate total capacity (accumulation)
T
q
that is needed for all
channels in the DVR (WITHOUT HDD) during
scheduled video recording
.
=
=
c
i
i
T
m
q
1
(3)
In the formula:
c
means total number of channels in one DVR (WITHOUT HDD)
Step 4: According to Formula (4) to calculate total capacity (accumulation)
that is needed for all
channels in DVR (WITHOUT HDD) during
alarm video recording (including motion detection)
.
=
=
c
i
i
T
m
q
1
×
a%
(4)
In the formula
%
means alarm occurrence rate
i
m
i
q
i
h
i
D
T
q