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8. Appendix
Appendix A-HDD Capacity/Recording Time Estimate
Calculate the maximum capacity of the build-in hard disk.
z
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
Record Quality
(Bit rate)
Frame Rate
(PAL/NTSC)
HDD Capacity
Recording Time(days)
4CH 8CH 16CH
Best(768Kbps)
Full Frame
Rate(30 or 25
CIF = 15 or
12.5 Half D1 =
7.5 or 6 D1)
500GB
15.8 7.9 3.9
High(640Kbps) 19.0
9.5
4.8
Middle(512Kbps) 23.7
11.9
5.9
Low(384Kbps) 31.6
15.8
7.9
Best(768Kbps)
750GB
23.7 11.9
5.9
High(640Kbps) 28.4
14.2
7.1
Middle(512Kbps) 35.6
17.8
8.9
Low(384Kbps) 47.4
23.7
11.8
Best(768Kbps)
1000GB
31.6 15.8
7.9
High(640Kbps) 37.9
19.0
9.5
Middle(512Kbps) 47.4
23.7
11.9
Low(384Kbps) 63.2
31.6
15.8
Best(768Kbps)
2000GB
63.2 31.6 15.8
High(640Kbps) 75.9
38.0
19.0
Middle(512Kbps) 94.8
47.4
23.8
Low(384Kbps) 126.4
63.2
31.6
Hard Disk capacity/recording time is only related to bite rate, neither Resolution, nor Frame rate
Calculate the compression bit rate for recording T hours.
z
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 the channels supposed as Dc is:
Dc = Dt *
（
8*1024
）
/ 3600 = Dt * 2.2756
（
Kbit/s
）