HDMI is an English acronym that refers to High Definition Multimedia Interface . This expression can be translated in our language as High Definition Multimedia Interface .
It is a standard that allows the transmission of high-definition digital video and uncompressed multichannel digital audio over a single cable . Companies such as Sony , Panasonic , Philips , Hitachi and Toshiba promoted this technology as a replacement for the scart connector , which required at least two cables.
Thanks to HDMI technology, it is possible to connect a device such as a video game console, a Blu-ray player or a computer (a computer) to a television . HDMI, in short, transmits video and audio between two devices using a single cable. This not only means greater convenience compared to old connectors that required more than one cable, but another advantage of HDMI is that its most common connector is relatively small compared to its predecessors.
The standard HDMI connector, known as type A , has 19 pins. HDMI type C and HDMI type D also have 19 pins, although they are smaller and are aimed at connecting portable devices (smartphones, tablets, etc.). There is also HDMI type B , 29 pins, whose use is not yet widespread, designed for future screens that will have higher resolution.
Since its creation, HDMI technology has been evolving to increase its capabilities. That is why it is possible to recognize several versions of HDMI, from HDMI 1.0 (which supports a maximum speed of 4.9 Gbps) to HDMI 2.1 (48 Gbps), passing through HDMI 1.2 , HDMI 1.3 , HDMI 1.4 and HDMI 2.0 .
It is important to mention that, although the HDMI standard does not establish a maximum length for cables, after a certain length the signal begins to attenuate.
Although HDMI is the most used technology to transmit high-resolution audio and video to all types of screens , there is also DisplayPort , a less popular alternative but which has certain advantages. Since its launch, DisplayPort offered users the possibility of transmitting an ultra high definition (UHD) signal, that is, 4k, at 60Hz, something that was only possible with HDMI with its version 2.0 and until then required the use of two HDMI 1.4 cables connected simultaneously to the display.
Since DisplayPort is less known than HDMI, it is common to find misinformation on the Internet when searching, whether to troubleshoot or purchase a cable. However, choosing one of these two technologies does not always depend on the preferences of each user, but in general they are limited to the options present on their devices . For example, if our laptop only has a mini DisplayPort output and our television or external monitor only has an HDMI output, we will have to get an adapter.
Regarding HDMI channel protocols, we can mention the following:
* TMDS : transmits video, audio and so-called "auxiliary" data. It can have a single or dual link signaling method, as seen in HDMI type A or B, respectively. The pixel frequency for video information ranges from 25 MHz to 330 MHz, and each pixel can have a depth of up to 24 bits, regardless of frequency. The maximum number of audio channels is eight;
* CEC : is based on the AV Link protocol. It is used for remote operations and has a two-way bus. Its definition took place with the HDMI 1.0 specification and is also known as Anynet , Aquos Link , BRAVIA Link , Regza Link , VIERA Link and EasyLink ;
* HDCP : This is a protocol to protect content from pirated copies, and means that certain audio and video files cannot be transmitted between certain devices via an HDMI cable.