Video monitoring system storage control, bandwidth calculation method

One , Basic concepts

1. Frame rate ： Is in the 1 Number of frames of pictures transmitted in seconds , It can also be understood that the graphics processor can refresh several times per second , Usually use fps（Frames Per Second） Express . Every frame is a still image , The fast and continuous display of frames creates the illusion of motion . A higher frame rate can make it smoother 、 More realistic animation

2. Bit rate ： The bits transmitted per second (bit) Count . Unit is bps(BitPerSecond),

Higher bit rate , The larger the data transmitted . Bit rate representation encoded ( Compress ) Aftertone 、 How many bits does video data need to be represented per second , And bit is the smallest unit in binary , Or 0, Or 1. Bit rate and tone 、 The relationship between video compression , Simply put, the higher the bit rate , The sound 、 The better the quality of the video , But the bigger the encoded file ; If the bit rate is less, the opposite is true .2 N+ T4 h4 s( q. C' R8 m 3 R8 P. m( g( t' { 3. Bit rate (DataRate)： It refers to the data flow used by video files in unit time , It is the most important part of picture quality control in video coding . At the same resolution , The larger the bitstream of the video file , The smaller the compression ratio , The higher the picture quality .

（1） Rate calculation formula

Bit rate = Sampling rate X Bit depth X channel

（2） file size

file size = Bit rate X Duration notes ： This calculation formula is applicable to uncompressed wav Format file is valid , Do not apply to mp3 And other compressed files .

（3） Some principles

a. The bit rate is proportional to the quality , But the file size is also proportional to the bit rate . This is to remember ;

b. The bit rate exceeds a certain value , Yes Images It doesn't have much effect on the quality of ;

c. If it is 1M Broadband , You can only see no more than 1024kbps In the video , exceed 1024kbps Your video can only be viewed smoothly after it is buffered .

4. The resolution of the ： Affect image size , It's proportional to the size of the image ： The higher the resolution , The bigger the image ; Lower resolution , The smaller the image .

Uplink bandwidth is the bandwidth of local information uploaded to the network .

Up speed It refers to the data transmission rate when the user's computer sends information to the network , For example, use FTP Upload files to the Internet , What affects the upload speed is “ Up speed ”. Downlink bandwidth is the bandwidth for downloading information from the network .

Down speed It refers to the data transmission rate when the user's computer downloads information from the network , For instance from FTP Download files from the server to the user's computer , What affects the down pass speed is “ Down speed ”." n

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Two 、 Transmission bandwidth calculation ：

Bit rate size × Number of cameras = The network bandwidth must be at least ;/ W5 g' f7 C; K$ E W notes ： The bandwidth of the monitoring point is the minimum bandwidth required for uplink ( The monitoring point uploads the video information to the monitoring center );

The bandwidth of the monitoring center is the minimum downlink bandwidth ( Download the video information of the monitoring point to the monitoring center );

example ： telecom 2Mbps Of ADSL Broadband ,50 Theoretically, the uplink bandwidth of the meter infrared camera is 512kbps=64kb/s, Its downlink bandwidth is 2Mbps=256kb/. example ： Monitoring is distributed in 5 A different place , Number of cameras in each place ：n=10(20 road )1 Monitoring centers , Remote monitoring and storage of video information , The storage time is 30 God .

The bandwidth and storage space of different video formats are calculated as follows ： s1 V* h 9 S; |) s, e$ l' K Local monitoring points ：

• aCIF The bit rate of each camera in video format is 512Kbps, That is, the data transmission bandwidth required by each camera is 512Kbps,10 The data transmission bandwidth required by the channel camera is ：7 j/ y: 512Kbps( Bit rate of video format )×10( Number of cameras )≈5120Kbps=5Mbps( Uplink bandwidth ) namely ： use CIF The network uplink bandwidth required for local monitoring in video format shall be at least 5Mbps;/[
• D1 The bit rate of each camera in video format is 1.5Mbps, That is, the data transmission bandwidth required by each camera is 1.5Mbps,10 The data transmission bandwidth required by the channel camera is ：$ 1.5Mbps( Bit rate of video format )×10( Number of cameras )=15Mbps( Uplink bandwidth ) namely ： use D1 The network uplink bandwidth required for local monitoring in video format shall be at least 15Mbps;
• 720P(100 Mega pixels ) The bit rate of each camera in the video format of is 2Mbps, That is, the data transmission bandwidth required by each camera is 2Mbps,10 The data transmission bandwidth required by the channel camera is ：2Mbps( Bit rate of video format )×10( Number of cameras )=20Mbps( Uplink bandwidth ) namely ： use 720P The network uplink bandwidth required for local monitoring shall be at least 20Mbps;8 t8 I
• 1080P(200 Mega pixels ) The bit rate of each camera in the video format of is 4Mbps, Zhejiang monitoring wholesale network coding board, that is, the data transmission bandwidth required by each camera is 4Mbps,10 The data transmission bandwidth required by the channel camera is ：4Mbps( Bit rate of video format )×10( Number of cameras )=40Mbps( Uplink bandwidth )3 namely ： use 1080P The network uplink bandwidth required for local monitoring shall be at least 40Mbps;)

The monitoring center ：

• CIF Bandwidth required for video format ： 512Kbps( Bit rate of video format )×50( The sum of the total number of cameras at the monitoring point )=Kbps=25Mbps( downstream bandwidth ) namely ： use CIF The network downlink bandwidth required by the video format monitoring center shall be at least 25Mbps5 ?
• D1 Bandwidth required for video format ： 1.5Mbps( Bit rate of video format )×50( The sum of the total number of cameras at the monitoring point )=75Mbps( downstream bandwidth ) namely ： use D1 The network downlink bandwidth required by the video format monitoring center shall be at least 75Mbps
• 720P(100 Mega pixels ) The required bandwidth of the video format ：% l$ T: `. @; ]. r+ g 2Mbps( Bit rate of video format )×50( The sum of the total number of cameras at the monitoring point )=100Mbps( downstream bandwidth )8 namely ： use 720P The network downlink bandwidth required by the video format monitoring center shall be at least 100Mbps
• 1080P(200 Mega pixels ) The required bandwidth of the video format ： 4Mbps( Bit rate of video format )×50( The sum of the total number of cameras at the monitoring point )=200Mbps( downstream bandwidth )' namely ： use 1080P The network downlink bandwidth required by the video format monitoring center shall be at least 200Mbps; \*

3、 ... and 、 Storage space calculation ：

There are several ways to store video images in the monitoring system

Technically possible are the following , But every manufacturer is not exactly the same ：

• IPC You can save... Locally （ Insert the memory card ）;
• Small scale solution front-end embedded NVR The built-in hard disk can store ;
• Large scale solution backend CVR The local hard disk of the storage platform or the local hard disk of the storage management server can store ;
• The back-end storage server of the large-scale solution can be attached IPSAN、NAS、FCSAN、 Private cloud storage ;

The size of the storage space = Bit rate × Time × Number of monitoring points ÷0.9( Loss of disk formatting 10% Space )

Expressed in the formula as ：

for example ： 50 Path storage 30 Days of 720P(100 Mega pixels ) The required storage space for video format recording information is ：

　　384kb/s×3600×24×30×50×1.1 ≈ 46.348TB

A list of the daily storage capacity required for a single camera

• 50 Path storage 30 Days of CIF The required storage space for video format recording information is ： 64×3600×24×30×50÷0.9=8789.1GB≈9TB 9 Y/ |' e. j; G b. Q1 |1 @+ L4 F$ F
• 50 Path storage 30 Days of D1 The required storage space for video format recording information is ：( 192×3600×24×30×50÷0.9=.2GB≈26TB6 p \7 T$ R5 c- k ! a- U1 D# T. P
• 50 Path storage 30 Days of 720P(100 Mega pixels ) The required storage space for video format recording information is ：( 256×3600×24×30×50÷0.9=.3GB≈35TB
• 50 Path storage 30 Days of 1080P(200 Mega pixels ) The required storage space for video format recording information is ： 512×3600×24×30×50÷0.9=.5GB≈69TB % a f