Dahua XVR, User Manual

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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
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
m
=
i
q
×
i
h
×
i
D
(2)
In the formula:
i
h
means the recording time for each day (hour)
i
D
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 during scheduled video recording .



c
i
i T
m q
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)
T
q
that is
needed for all channels in DVR during alarm video recording (including motion
detection) .



c
i
i T
m q
1
× a% (4)
In the formula
：
a% means alarm occurrence rate
You can refer to the following sheet for the file size in one hour per channel. (All the data
listed below are for reference only.)
Bit stream size
（
max
）
File size Bit stream size
（
max
）
File size
96K 42M 128K 56M
160K 70M 192K 84M
224K 98M 256K 112M
320K 140M 384K 168M