286
7 Appendix A HDD Capacity Calculation
Calculate total capacity needed by each device according to video recording (video recording type and
video file storage time).
Step 1: According to Formula (1) to calculate storage capacity
that is the capacity of each channel
needed for each hour, unit Mbyte.
102436008 
ii
dq
means the bit rate, unit Kbit/s
Step 2: After video time requirement is confirmed, according to Formula (2) to calculate the storage
capacity
, which is storage of each channel needed unit Mbyte.
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)
that is needed for all
channels in the device during scheduled video recording.
means total number of channels in one device
Step 4: According to Formula (4) to calculate total capacity (accumulation)
that is needed for all
channels in device during alarm video recording (including motion detection).
×a% (4)
In the formula:a% means alarm occurrence rate