Dahua Technology XVR4 Series, User Manual

Page: 311 / 330

HDD Capacity Calculation 298
HDD Capacity Calculation Appendix 2
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 Step 1
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 Step 2
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 Step 3
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 Step 4
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.)
Bit stream size
（
max
）
File size Bit stream size
（
max
）
File size
96Kbps 42MB 128Kbps 56MB
160Kbps 70MB 192Kbps 84MB
224Kbps 98MB 256Kbps 112MB
320Kbps 140MB 384Kbps 168MB
448Kbps 196MB 512Kbps 225MB
i
m
i
q
i
h
i
D
T
q