Company News

This article mainly shares the knowledge about HDMI and how to choose a good HDMI cable. Now the HDMI interface has become a common HD video transmission interface in our life, and has penetrated into all aspects of our work and life, such as laptop connected to the projector, computer connected to the monitor, set-top box connected to the TV and so on. All of them have HDMI ports.

There are many versions of the HDMI protocol, such as HDMI1.4, HDMI2.0, HDMI2.1, and so on. HDMI cables are divided into optical fiber HDMI cables and ordinary HDMI cables, which are suitable for different scenarios.

Choose an appropriate length of HDMI cable. It is recommended not to use an HDMI cable longer than 10 meters, because after 10 meters, the data transmission stability of 1920*1080p50 display frame rate.

First, HDMI expertise

1. HDMI protocol

HDMI, short for High Definition Multimedia Interface, can be used to send uncompressed video and audio data instead of digital signals.

Use an HDMI cable to connect the two devices. If one of the devices does not have an HDMI port, consider a conversion cable or converter.

Note that the use of HDMI is actually required to pay copyright fees, generally product design manufacturers have paid, there is an annual membership fee or product sales fee to calculate, so this is the majority of graphics cards are using free DP line.

(1) Interface size

According to different sizes, it can be divided into standard HDMI port, mini HDMI port and mini HDMI port, as shown in the figure below:

(2) Interface version

HDMI versions are shown in the following figure, including color gamut, format, audio channel, video data, etc.

HDMI1.3 or later: supports a maximum of 1920*1080 format.

HDMI1.4: Supports 3840*2160@30p at most.

HDMI2.0 version:

Can support 3840*2160@60p, support up to 32 audio channels.

Hdmi2.0a and HDMi2.0b Support HDR based on HDMI2.0.

HDMI2.1: Support 8K@60p, 4K@120p, dynamic HDR.

2. HDMI cable

(1) Wire core material

The cable used by ordinary HDMI cable is copper cable core, and the cable used by optical fiber HDMI cable is fiber core. Material is not the same, determines the fiber HMDI and ordinary HDMI in appearance, picture quality, transmission rate and other aspects of the great difference, of course, in general, ordinary HDMI cable is enough, the price of fiber HDMI cable is expensive.

Ordinary HDMI cable short distance transmission, the general recommendation is 10 meters, good transmission performance, but long distance transmission, copper core transmission loss, signal attenuation, data transmission stability is greatly reduced, and will produce electromagnetic interference.

Fiber cores can be subdivided into glass fiber and plastic fiber. Glass fiber loses less, but plastic fiber costs less. In order to ensure transmission performance, it is generally recommended to use plastic fiber for distances below 50 meters and glass fiber for distances above 50 meters. At present, glass fiber is the most widely used in the world, which has many excellent characteristics, such as lightweight, slim, flexible, lossless transmission and so on. Thinner, lighter and softer than regular HDMI cables, but more expensive.

(2) Built-in chip

Optical fiber HDMI cable internal transmission is the optical signal, for the external incoming or sent to the external video signal is electrical signal, which requires the photoelectric conversion chip, through two photoelectric conversion to achieve signal transmission, this is the reason why the optical fiber HDMI cable transmission performance is stronger.

Copper HDMI cables directly use electrical signals for transmission without the need for two photoelectric conversions, but signal attenuation increases with distance. If you need to transmit over long distances, you need an HDMI repeater and signal amplifier.

(3) Transmission distance

Ordinary HDMI cable short distance transmission, the general recommendation is 10 meters, can also transmit 4k, 8K signal.

Optical fiber HDMI cable due to the use of optical fiber medium, in the long distance transmission loss can be almost negligible, the maximum transmission distance can reach 100 meters or 500 meters.

(4) Price difference

Due to the different material and wire structure, the price of ordinary HDMI cable is cheap, according to the transmission of the video frame rate is different, the price from 10 to 100 different price products are available. The price of optical fiber HDMI cable is more expensive, basically more than 100.

(5) Application scenarios

Ordinary HDMI cables are suitable for most scenarios and do not require long distance transmission.

Optical fiber HDMI cable can be used in various occasions that need to output high-definition image display equipment and large area wiring connection, such as: home theater system, remote information release system, public security high-definition monitoring system, broadcast and television control system, high-definition video conference office system, large medical image system, multimedia system, industrial automation system and so on.