Introduction of 4K video signal resolution and transmission bandwidth

2018-11-02 11:16:07 Guangzhou Xunkong


4K signal refers to ultra HD video signal with 4K resolution, in which 1 “K” is equivalent to 1024 pixels, since in the field of computer science it is all represented as a carry of 1024. There are two kinds of common resolution of 4K signal, one is 3840*2160 (based on the 2K signal's 1920*1080 resolution), and the other is 4096*2160 (cinema 4K film specification).

Given 4K signal resolution, how much video bandwidth does our transmission device,such the matrix switcher, need to transmit 4K signals?

We take the transmission resolution of 3840* 2160@30Hz as an example, and the video bandwidth required is calculated as follows:

3840*2160*8*3*30=5.97Gbps (Color depth 8 bit, RGB 3 colors), This is the theoretical value, and the actual transmission efficiency may only reach 80%. Therefore, the interface bandwidth of 4K/30Hz for stable transmission is about: 5.97/0.8=7.4Gbps. 

Let's take a look at the standard transmission bandwidth of many HD video interfaces:

3G-SDI: 2.97Gbps

DVI: About 3.2Gbps

6G-SDI: 6Gbps

HDMI(1.4): 10.2Gbps

12G-SDI : 12Gbps

HDMI(2.0): 18Gbps

DP(1.4): 32Gbps

HDMI(2.1): 48Gbps

The transmission bandwidth of the interface from above we can know that to transmit 4K signal, we need bandwidth of 7.4 Gbps at least. So only HDMI version 1.4 and above, 12 G-SDI and the latest DP interface can meet the bandwidth requirements. And if you want to transfer the4K video signal of 60 Hz, the bandwidth will be doubled to about 14.8 Gbps. Now we can only use DP 1.4 interface or HDMI version 2.0 and above to make it (HDMI 2.0 and HDMI 2.1 also supports UWB display of 16:9).

Xunkong seamless hybrid matrix switcher perfectly supports 4K signal transmission