How to calculate the bandwidth of video transmission? How much bandwidth is required to transmit 4K video?

In the practical application of video surveillance , Many configurations will affect the quality of video transmission , Like clarity 、 Bit rate 、 Video storage space, etc , Related to these contents , Is the bandwidth of the network . Many users don't know how to convert the concept of bandwidth , In many HD video transmission projects , It is also difficult to calculate the bandwidth requirements of video , Therefore, this paper comprehensively introduces the concept and calculation of bandwidth .

Bandwidth is divided into several types ？

Bandwidth includes uplink bandwidth and downlink bandwidth .

Uplink bandwidth refers to the bandwidth from local audio and video information to the network , Uplink rate refers to the rate at which the user's computer sends information to the network . For example EasyDSS Audio and video transmission , The front-end equipment uploads video to the network platform in real time , What affects the upload speed is the uplink rate .

Downlink bandwidth is the bandwidth for downloading video from the network , Downlink rate is the data transmission rate when users cache content from the network . For example EasyDSS Audio and video transmission , When users watch live video from a computer or mobile phone , What affects the viewing rate is the downlink rate .

How to calculate bandwidth ？

Bandwidth calculation formula ： Bit rate size * Number of cameras = Minimum network bandwidth . In general , The minimum downlink bandwidth is required when monitoring the bandwidth of the point .

Well, as HD video transmission 4K The signal , How much bandwidth should the network reach to meet the demand ？4K There are two common resolutions of signals , Namely 38402160 and 40962160 ( The cinema 4K Film specifications ). We transmit [email protected] Resolution, for example , The video bandwidth required is calculated as follows ：3840216083*30=5.97Gbps.

However, the calculation result is the theoretical value , The actual transmission efficiency may only reach 80%, So we need to stabilize the transmission 4K 30Hz The signal of , The interface bandwidth is about 5.97/0.8=7.4Gbps.

How to save bandwidth in video transmission ？

This step of saving bandwidth can be mainly in the setting of camera , If the camera supports bitrate , The camera can be adjusted to variable bit rate . Besides , Some cameras also support dual code streams , That is, main code stream and sub code stream , Compared with the main code stream , The flexibility of sub code stream can be higher , When HD transmission is not required , Reduce the bit rate of sub code stream , It can also save bandwidth .