There are many articles about TV, speaker and decoder, but there is little popular science about wire. In recent days, there have been many detours in the layout of home cinemas, so I specially wrote an original to share my experience and give you a guide.
Difference between HDMI and DP
At present, there are two mainstream video transmission cables: DP (Display Port) and HDMI (high definition multimedia interface). Since too many people don't understand the difference between them, I'd like to share some information here from home theater establishment.
HDMI is mainly led by Sony, Philips, Panasonic, Toshiba. It is specially designed for home theater, audio-visual and other equipment, which requires the detection and certification of the testing center authorized by ATC (HDMI forum authorized testing center).
DP is dominated by AMD, Intel, ASUS, Dell, free of certification and authorization, and aims to replace HDMI interface (the full-function USB type-C interface video signal adopts DP protocol). Therefore, generally, PC monitors have DP and HDMI interfaces, while TV, Blu-ray players, echo walls, speakers and other home theater equipment only have HDMI interfaces.
From the perspective of usage, HDMI has an eARC return function to facilitate equipment connecting, while DP does not. DP is also a hot-plug interface, which will be automatically disconnected when the display device is turned off, while HDMI interface will not. The intuitive experience is that when your desktop host connects dual monitors by HDMI, and turns off one monitor, the win system will not recognize the single screen, but continue double screen model. If connecting two displays by DP, the win system will automatically switch to the single screen mode and withdraw the window after turning off one (the phenomenon of the former win system, the win11 system has been refined ).
HDMI classification
HDMI has over 20 years history, and there are many physical interfaces and protocol versions. I'll give you a brief review.
Physical classification
In terms of physical interfaces, HDMI now has five interfaces that are still in use, such as a, B, C, D and E.
HDMI type-A, also known as standard HDMI cable, is the most common one, with a total of 19 pins. With the advent of HDMI 1.0 protocol, it is mainly to replace the single channel DVI-D interface. HDMI type-B interface, also known as dual channel HDMI interface, is commonly used in professional audio devices, with a total of 29 pins. With the advent of HDMI 1.0 protocol,it is mainly to replace the dual channel DVI-D
HDMI type-C interface, also known as mini HDMI interface, appears after HDMI 1.3 protocol published, which is mostly seen on mini SLR cameras and tablets. It is smaller than HDMI type-A interface, but it still has 19 pins. Although the number of pins is the same, the definitions are different. HDMI 1.4 protocol adds DMI type-D interface, also known as micro HDMI, which is smaller than Mini HDMI interface and somewhat similar to micro USB interface. Double row design, so there are 19 stitches still. HDMI type-E is also increased with HDMI 1.4 protocol, mainly in industrial fields such as autonomous driving, which will not be discussed for civil use.
Protocol classification
For bandwidth growth demand, HDMI wire has been updated in several versions, and the latest version is HDMI 2.1A.
In addition to bandwidth differences, there are also functional differences, like color depth and color space.
HDMI wires of different protocol versions differ in the core diameter, shielding layer and length of conductive materials. Therefore, there will be color differences between different HDMI lines, which is not metaphysics.
Shopping guide
1> Look at the certification label
In order to simplify the version, the HDMI association started the version integration, taking HDMI 2.0 as a subset of HDMI 2.1. As a result, there is a confusion that the HDMI 2.0 interface, which originally had a maximum bandwidth of 18gb, can rightly label itself as HDMI 2.1 interface; The HDMI 2.0 wires can also label itself HDMI 2.1.
XXS： 4K@120Hz （YCbCr4:4:4 ）10bit =40Gb
PS5： 4K@120Hz （YCbCr4:2:2） 10bit = 24.8Gb
However, devices with true HDMI 2.1 specifications, such as next-generation game consoles, require a bandwidth of more than 18gb. If you buy unqualified wires, you can't realize it 4K@120Hz 10bit picture.
Therefore, when you buy HDMI cables, you should not look at the protocol label, but at the certification label.
HDMI (standard): 1080i or 720p, with a maximum bandwidth of 4.95, equivalent to HDMI 1.0-1.2.
Standard with Ethernet: add Ethernet transmission function on the basic version.
Standard with automotive: industrial functions are added to the standard version.
High speed HDMI (high speed): support 1080p, with a maximum bandwidth of 10.2, equivalent to HDMI 1.3-1.4.
High speed with Ethernet: add Ethernet transmission function on the basic high speed version.
High speed with automotive: industrial functions are added on the basic high speed version.
Premium high speed: 4K@60Hz , equivalent to HDMI 2.0.
Ultra high speed: 8K@60Hz and 4K@120Hz , equivalent to HDMI 2.1.
Because the HDMI+number form makes it difficult for consumers to distinguish, HDMI association has made certification labels for public choice. In 2010 it announced that it will start to cancel the identification protocol version on products from 2012. HDMI wire that conforms to ATC certification and testing will have the certification mark on the box.
2>Look at the wire core
Only after disassembling the wire core, can we know the actual situation, so we can only rely on the information provided by the company for comparison and reference.
Copper will be used for its good ductility, heat conductivity and conductivity. Regular HDMI lines often use electrolytic copper, and some high-end ones adopts oxygen free copper, silver plated copper etc., which are soft and tough. Unqualified HDMI lines often use recycled copper with many impurities, even copper-clad iron and copper-clad aluminum. The low-end cords has short service life, is hard and brittle.
3>To look at the number of cores.
The standard HDMI cable is 19 pins, with 20 cores inside (19 for data transmission and 1 for grounding). Because there are 4 non-essential shielded wires in the 19 pin definition of HDMI, unqualified HDMI lines will omit them to lower costs, with only 16 lines.
If possible, you can use this HDMI test board with a multi-meter to check whether it is 20 wires.
4> we can look on the wire diameter. The standard HDMI 2.1 wire uses 28# or 30#, 0.36mm. Theoretically, the thicker the wires, the more conducive it is to signal transmission, so we also have products of 24#/0.54mm and 23#/0.60mm wires.
5>Look at the appearance
There are two common HDMI lines: round and flat. The round is recommended. The flat line has only two angles, but the round line can be bent at any angles, which is more conducive to wiring.
6>In addition to the shape, we will also see the skin material.
HDMI has high requirements for shielding. Unqualified HDMI cords are not well shielded, which will lead to problems such as picture wiring, snowflakes, etc. Conventional HDMI lines are generally covered with PVC on the outside and aluminum foil on the second layer. High quality cords will have three layers of shielding, the outermost is PVC, the middle is tinned copper and the inner is aluminum foil shielding layer.
The outer skin of this 8K ultra-high definition cable on the hand is nylon wire +pet fabric woven.High temperature resistance, well protection, not easy to damage.
Some HDMI wires are also covered with a magnetic ring, claiming anti-interference. However, according to the shielding scheme of HDMI, compliant products do not need magnetic rings, and the presence or absence of magnetic rings has little impact.
7>Look at the interface
The interface is the most fragile part of the wire. Unqualified products can't stand many times of plugging, and will rust, loosen and have poor contact. To prevent interface oxidation, smooth and bright gold-plated interface products are recommended. The cost of gold plating is low, and most manufacturers can do it with HDMI wires.In order to be plug-gable, the interface shell had better choose the product of integrated die-casting process, which is more wear-resistant and fall resistant. This silver plated 8K ultra-high definition cable has a zinc alloy shell with integrated die-casting process, and there are ice crystal dark lines on the surface, which is not only beautiful and exquisite, but also easy to identify, and it is easy to distinguish when wiring. There is also a concave design on both sides, which is convenient for plugging and pinching.
8>Function measurement
If you buy HDMI wire without label and only abbreviated protocol, you can identity weather it is true HDMI 2.1 or not by testing only. It can be seen that the HDMI signal format is enhanced format (VRR).Check the video output information , it supports HDR and VRR. In terms of refresh rate, 120Hz output is available.Compliance with the above settings indicates that the wire meets HDMI 2.1.
Guangdong Weallans Electronics Technology Co., Ltd. is a professional manufacture of HDMI cables. Our products can get through all those testing and detection. If you have any other experience of distinguish a qualified HDMI cable, please let us know.