Dahua Technology DH-XVR42 AN-I Series, User Manual

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User’s Manual
359
HDD Capacity Calculation
Calculate total capacity needed by each DVR according to video recording (video recording type and
video file storage time).
According to Formula (1) to calculate storage capacity
i
q
that is the capacity of each
channel needed for each hour, unit MB.
Formula (1):
1024 3600 8
÷ × ÷ =
i i
d q
In the formula:
i
d
means the bit rate, unit Kbit/s
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 MB.
Formula (2): = ×
i
h
×
i
D
In the formula:

means the recording time for each day (hour)

means number of days for which the video shall be kept
According to Formula (3) to calculate total capacity (accumulation)
T
q
that is needed for all
channels in the DVR during scheduled video recording.
Formula (3):
∑
=
=
c
i
i T
m q
1
In the formula:
c
means total number of channels in one DVR
According to Formula (4) to calculate total capacity (accumulation) that is needed for all
channels in DVR during alarm video recording (including motion detection).
Formula (4):
∑
=
=
c
i
i T
m q
1
×
a%
In the formula
：
a%
means alarm occurrence rate
You can refer to the following table for the file size in one hour per channel. (All the data listed below
are for reference only.)
Appendix Table 2-1 HDD capacity calculation
Bit Stream Size (max) File Size Bit Stream Size (max) File Size
96 Kbps 42 MB 128 Kbps 56 MB
160 Kbps 70 MB 192 Kbps 84 MB
224 Kbps 98 MB 256 Kbps 112 MB
i
m
i
q
i
h
i
D
T
q