The resolutions of video surveillance images include CIF, D1, 720P, and 1080P. These resolutions have typical bit rates such as 512 Kbp/s, 1 Mbit/s, 2 Mbit/s, 4 Mbit/s, and 8 Mbit/s. In fact, regardless of the analog image or digital image, the video storage capacity is calculated based on the bit rate, not the resolution.
The formula for calculating the storage capacity is as follows:
Storage capacity (unit: GB) for 1 hour of a camera whose bit rate is n (unit: Mbit/s) = [(n/8) x 3600]/1024 GB
To be specific:
n/8 converts the unit from Mbps to MBps.
n MBps x 3600 equals to the storage capacity in one hour (unit: MB).
n x 3600/1024 converts the unit from MB to GB.
The following table lists the calculated storage capacity of a camera for one hour and one day in common bit rates. The calculation result is not an accurate value and is rounded off.
The following provides an example to describe how to calculate the raw capacity required for storing video images. Assume that there are 100 IPC cameras of 720P, the storage bit rate is set to 2 Mbit/s, all day recording is required, and the storage duration is 30 days.
The calculation process is as follows:
1. Calculate the raw storage capacity required by a single camera every day.
[2 Mb/s x 3600s/h x 24h]/8 = 21.1 GB
2. Calculate the raw storage capacity required by a single camera for 30 days.
[2 Mb/s x 3600s/h x 24h]/8 x 30 = 633 GB
3. Calculate the raw storage capacity of 100 cameras for 30 days.
[2 Mb/s x 3600s/h x 24h]/8 x 30 x 100 = 63300 GB/1024 = 61.8 TB
VCN3020 is used as an example.
To meet the 61.8 TB video storage capacity requirement, you need to configure 11 pieces of 6 TB hard disks and one hot spare disk as a RAID 5 array.
The storage server can be fully configured with 38 hard disks which is divided into 3 RAID groups (12 disks in each group) and 2 hot spare disks. In this case, 11 pieces of storage hard disks can be used. A total of 33 pieces of 4 TB hard disks can be used. The total capacity is 132 TB.
The maximum number of cameras that can be connected to a server (storage duration: 30 days) is calculated as follows: 132/(633/1024) = 213