What is an HDMI cable?

HDMI cable stands for High-Definition Multimedia port Cable and is capable of transmitting uncompressed high definition video and multi-channel audio data at up to 5Gbps with high quality while eliminating the need for digital-to-analog or analog-to-digital conversion prior to signal transmission, ensuring the highest quality audio and video signal transmission.

The HDMI cable supports a 5Gbps data transfer rate up to 30 meters, which is sufficient for one 1080p video and one 8-channel audio signal. Because the demand for a 1080p video and an 8-channel audio signal is less than 4GB/s, the HDMI cable has a lot of headroom. In addition, HDMI supports EDID, DDC2B, so devices with HDMI have a "plug-and-play" feature where the source and display device automatically "negotiate", automatically selecting the most appropriate video/audio format.

HDMI cable material and types

Material

High density colored nylon braided mesh + high-quality injection-molded iron powder magnetic core + double-sided 4-layer aluminum foil and high-density double shielding braided mesh + pure copper tinned anti-oxidation core + plug copper shell gold-plated 15U".

Types

According to the difference of electrical structure and physical shape, HDMI cables can be divided into four types: Type A, Type B, Type C, and Type D.

HDMI cables

HDMI (TYPE A): A type A HDMI cable is used in HDMI version 1.0, with a total of 19 pins and a specification of 4.45 mm × 13.9 mm. It is the most common HDMI connector specification, equivalent to point-to-point DVI Single-Link transmission. Before HDMI 1.2a, the maximum transmission can be 165 MHz TMDS, so the maximum transmission specification can only lie in 1600 x 1200 (TMDS 162.0 MHz).

Mini-HDMI (TYPE C): Mini-HDMI cable is applied to HDMI 1.3 version, a total of 19pin. It can be said to be a reduced version of HDMI A type, the specifications of 2.42 mm × 10.42 mm, but the definition of the pin position has changed. It is mainly used in portable devices, such as DV, digital cameras, portable multimedia players, etc. Due to the size limitation, some graphics cards will use mini-HDMI, users must use an adapter to convert to standard size Type A before connecting to the display.

Micro HDMI (TYPE D): Micro HDMI cable is applied to HDMI version 1.4, with a total of 19 pins and specifications of 2.8 mm x 6.4 mm, but with a change in footprint definition. The new Micro HDMI will be about 50% smaller than the current 19-pin MINI HDMI version port, which can bring up to 1080p resolution support and the fastest 5GB transmission speed for cameras, cell phones, and other portable devices.

HDMI ports

A, C and D types are introduced here, so is there a type B? The answer is yes, except that there are no products that use this port, so it will not be introduced here.

Development of HDMI

In 2002, the earliest version of HDMI 1.0 was launched, with a maximum bandwidth of 4.95 Gbps. Video support for DVD and Blu-ray, Rec. 709 color gamut. Audio support for 8-channel PCM, 24bit / 192kHz audio source. In other words, HDMI 1.0 can already support 1080p Full HD resolution and a 7.1 audio system.

In 2004, HDMI version 1.1 added support for DVD-Audio.

In 2005, HDMI version 1.2 added DSD lossless format to the support list

In 2006, HDMI version 1.3 increased the bandwidth to 10.2 Gbps, support for xvYCC wide color gamut, audio unlocked Dolby TrueHD and DTS-HDMA, and other new audio technologies. After that, 1.3a, 1.3b, 1.3b1, 1.3c, and other minor changes were introduced one after another; in the same year, the world's first Blu-ray player SamsungBD-P1000 was launched, already equipped with an HDMI port.

In 2009, HDMI 1.4, the first HDMI version supporting 4K30p and 3D, was introduced, and the 100Mbps network transmission function was added.

In 2013, HDMI 2.0 bandwidth from 10.2Gbps to 18Gbps, support for 4K60p and compatible with Rec. 2020 color depth. The audio side began to support 32-channel audio sources.

In 2015, HDMI 2.0a added support for HDR, and HDMI 2.0b added support for another high dynamic range technology, HLG.

In 2017, HDMI 2.1 increased the bandwidth to 48Gbps in one breath, supporting 8K/60Hz, 4K/120Hz format video, 16bit color depth, and the ability to transmit dynamic HDR data.

Comparison between HDMI cable and DP cable

These two cables are now considered the mainstream digital cable. The chart below is a brief comparison between the two.

Since DP came out later, DP has had the advantage under the latest standards. However, HDMI 2.0 and DP1.4 are still dominant on the market. HDMI 2.1 has already come out with some corresponding products such as TVs and graphics cards. 

In daily use, the HDMI popularity is relatively higher. TVs, computer monitors, set-top boxes, etc. are relatively easy to find HDMI ports. Personal opinion, considering that HDMI has a patent fee, the major manufacturers should prefer free DP, the future development of DP may be better.

Fiber optic HDMI cable

With the promotion of the 5G network and 8K HD, announcing that the market as a whole began to step into the era of HD, and HDMI cable has become a must for transmission of HD audio and video. HDMI cables appearing on the market today are mainly copper and AOC pure fiber optic cable and photoelectric composite HDMI cable. HDMI cable using optical fiber as the transmission medium will begin to form the mainstream. Next, we talk about what is the fiber optic HDMI cable and the advantages of fiber optic HDMI cable.

Optical fiber is a transmission medium used to transmit optical signals while HDMI is a high-definition multimedia port that can receive and send compressed digital audio and video information. The traditional HDMI cable transmission material is a copper core, while the fiber optic HDMI cable will change the transmission material to optical fiber.

The advantages of fiber optic HDMI cable

Due to the difference in attenuation parameters of copper cables, distortion may occur after the transmission distance of more than 7.5 meters on a copper core HDMI cable. For projectors and surveillance video equipment, the transmission with copper-core HDMI cable will directly lead to poor experience of ultra-clear devices. But using fiber optic HDMI cable, users do not have to worry about these problems. Fiber optic HDMI cable uses photoelectric conversion technology, so the long-distance signal transmission attenuation is almost zero, and the transmission distance of up to 500 meters.

Low-speed signal transmission using copper wire, high-speed data transmission using optical fiber. This is the current market commonly used a combination of fiber optic HDMI cable. But in theory, the low-speed signal copper wire transmission will cause length problems. So we see the problem of photoelectric hybrid cable transmission distance is caused by the low-speed handshake signal copper cable. High-speed data transmission using optical fiber transmission. Converting the original electrical signal into an optical signal, there is no such thing as loss.

Fiber optic HDMI cable is an optical signal transmission, free from external electromagnetic interference. It can achieve true lossless transmission, to ensure that the transmission of high authenticity, especially for the transmission of audio with high material requirements.

We have reason to believe that in the future, fiber optic HDMI cables will become the necessary wire for HD transmission. Traditional HDMI high-definition cable is subject to signal attenuation, and it is difficult to meet the high bandwidth transmission requirements of 18Gbps. Fiber optic HDMI cable does not need to worry about the transmission bandwidth problem, you can enjoy the sound quality and colorful HD images!