ZMODO 16CH DVR, User Manual

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User Manual for Zmodo DVR
36
5.2 Methods of Calculating HDD Capacity
1) Calculate the maximum capacity of the build-in hard disk.
*Timing Recording:
Step 1: Calculate the maximum capacity of the hard disk needed in selected channel per hour, suppose
as Si (MByte) (i is the channel number), and suppose the bit rate of the channel selected as D (Kbit/s).
The formula of calculation is:
Si =
（
D*3600
）
/
（
8*1024
）
= D * 0.439453125 MB
Step 2: Confirm the storage time length, suppose as T hours. The total maximum capacity of the hard
disk needed in selected channel for T hours, suppose as St is:
St = T * S1
Step 3: Confirm the total numbers of the channels, suppose as n. The total maximum capacity of the
hard disk needed, suppose as Sc is:
Sc = S1 + S2 + … + Sn
Alarm Recording:
Suppose the rate of alarming as
α%. The capacity of the hard disk needed in alarm recording supposed
as Sa is:
Sa = Sc *
α%
2) Calculate the compression bit rate for recording T hours.
*Timing Recording
Step 1: Suppose the capacity of the hard disk as S, the total numbers of the channel as n. The capacity
of hard disk needed per channel supposed as Di is:
Di = S / n
Step 2: Suppose the total recording time as T hours. The capacity of the hard disk needed per hour per
channel supposed as Dt is:
Dt = Di / T
Step 3: The bit rate of all channels supposed as Dc is:
Dc = Dt *
（
8*1024
）
/ 3600 = Dt * 2.2756
（
Kbit/s
）