Behind we have left the scart, and now all televisions or devices use some type of HDMI cable connector. HDMI stands for "HDMI", or High Definition Multimedia Interface. It includes a connector and a data transmission protocol for video, image and sound that is updated with new generations to offer more options.
The HDMi cable transmits image and sound in an uncompressed protocol and is the most widely used connector today, having almost completely replaced the VGA cable connectors and the AV scart, which is now only found in older televisions. Today we find it in any device that can emit or receive image and audio, such as the image output of graphic cards and motherboards in PCs, televisions, and even tablets.
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HDMI Features
The connection via HDMI cable allows you to send and receive video and audio without image compression, since it does not go through an encapsulation of data in the MPEG format, as happens with ATSC and DVB connections. The data is sent to a decoder that outputs the data uncompressed, encoded in TMDS format, and sent to the receiving device.
the connection with the HDMI cable makes it impossible to make copies of the audiovisual content that is transmitted through them. Manufacturers who want to use this connection must authorize it at HDMI consortium, which will give them an authorization code to make connectors. If that brand is found to manufacture devices that allow copying, that number is added to a list of manufacturers and the devices manufactured from now on will not be able to interact with those of the brand.
HDMI cable connector pinouts
The following list of pins indicates what information it carries and what protocol each of the connectors of an HDMI cable receiver uses.
- Pin 1: TMDS Data2 +
- Pin 2: TMDS Data2 Shield
- Pin 3: TMDS Data2–
- Pin 4: TMDS Data1 +
- Pin 5: TMDS Data1 Shield
- Pin 6: TMDS Data1–
- Pin 7: TMDS Data0 +
- Pin 8: TMDS Data0 Shield
- Pin 9: TMDS Data0–
- Pin 10: TMDS Clock +
- Pin 11: TMDS Clock Shield
- Pin 12: TMDS Clock–
- Pin 13: CEC
- Pin 14: Reserved (NC on device)
- Pin 15: SCL
- Pin 16: SDA
- Pin 17: DDC / CEC Ground
- Pin 18: +5V Power (max 50mA)
- Pin 19: Hot Plug Detect
The TMDS channel is in charge of carrying audio, video and auxiliary data. It has a video pixel frequency that ranges from 25 MHz to 165 MHz if it is an HDMI type A, or 330 MHz if it is an HDMI type B. Its audio sampling reaches the frequencies 32 kHz, 44,1 kHz , 48 kHz, 88,2 kHz, 96kHz, 176,4 kHz, and 192 kHz. It has up to 9 audio channels.
On the other hand, the CEC channel found on pin 13 is optional, and uses the standard AV Link protocol. Used for remote control functions. The CEC channel is also known as Anynet on Samsung devices; Aquos Link on the Sharp; BRAVIA Sync or BRAVIA Link on Sony TVs; Kuro Link at Pioneer; CE-Link and Regza Link on Toshiba televisions; RIHD (Remote Interactive over HDMI) for Onkyo devices; Simplink on LG televisions; HDAVI Control, EZ-Sync, VIERA Link on Panasonic televisions; EasyLink for Philips; and NetCommand for HDMI in those of the Mitsubishi brand.
HDMI Generations
As technology has advanced, the HDMi cable has been presenting new features in its connectors and its protocol for sending image and sound. There are several generations of HDMI, each one introducing new features to the previous generation.
HDMI 1.0
Launched in 2003 after its presentation in December 2002. It consists of a single cable with a maximum transfer rate of 4,9 Gbit / s. It has support for up to 165 Mpixels / s in video mode and 8 channels / 192 khz / 24-bit audio.
HDMI 1.1
This version added support for DVD Audio.
HDMI 1.2
One Bit Audio was added, a support of up to 8 channels used in Super Audio CD. In addition, you are allowed to use custom resolutions without having to be previously approved by the HDMI consortium.
HDMI 1.3
Increase the bandwidth to 340 Mhz, which is equivalent to 10,2 Gbit / s; Dobly TrueHD and DTS-HD, low-loss audio formats used in HD-DVD and Blu-Ray players. Small-size connector format for camcorders is introduced via cam link.
HDMI 1.4
The physical interface of this generation allows sending 3D video. From this generation, the resolution goes from Full HD to XHD, to support videos of up to 4096 × 2160 pixels if they go at 24 frames per second, or 3840 × 2160 pixels if they go at 30 frames per second. Color support is improved when connecting video cameras, and image quality is maintained even with motor vibrations or electrical noise.
By having an audio return channel, it can be used for stereos and thus have fewer cables. It is allowed to send and receive data through an Ethernet connection of up to 100Mbit / s.
HDMI 2.0
Available from September 2013. Increase bandwidth to 18 Gbit / s. This achieves 4K resolution at 50 or 60 frames per second, 32 audio channels of up to 1536 Khz. This generation allows the simultaneous delivery of 2 video streams in the event that there are several users on the same screen; and audio streaming for four users. Support is added for the 21: 9 aspect ratio.
HDMI 2.0b
Dynamic synchronization of video and audio stream is added. Adds support for CEC extensions. It offers two video outputs on the same screen as well as simultaneous audio outputs, which grow to four. Screen format in 21:9 ratio is supported. Dynamic synchronization of video and audio stream is added.
HDMI 2.1
The most recent generation to date. It was launched in November 2017. Its bandwidth reaches up to 48 Gb/s and allows resolution of up to 10K. Supports dynamic HDR so that the color is corrected at each frame. In the case of video games, it allows VRR and ALLM.
At its launch it absorbed all the HDMI 2.1 protocol and now that a connector or cable has one of the new features of 2.1, it can announce that it has it despite not fully complying with the protocol.
HDMI 2.1
Introduced at CES 202, HDMI 2.1a is a revision of generation 2.1 that adds source-based tone mapping, or SBTM. SBTM is a new HDR feature that offloads some of the HDR tone mapping to the content source along with the tone mapping performed by the TV or monitor.
Is a more expensive HDMI cable worth it?
The short answer is that an expensive HDMI cable is not worth it compared to a cheaper one. Expensive cables can boast of being braided or having special features, but in reality, it is more interesting that they are certified. If both cables are certified to the same generation, the best choice is the cheap HDMI cable because it will give you the same as him expensive HDMI cable.
There can be notable differences such as the length of the HDMI cable, which will matter to us if we have to connect equipment that is physically far from each other. One of the reasons to go for a more expensive cable is to go for one of an older generation, but only if both devices that we are going to connect are compatible with that cable. HDMI generation.
Disadvantages of HDMI
Despite being massively adopted and offering a much simpler installation, it has been seen that HDMI cables they are prone to bugs even at the household level. Connectors are prone to damage from bumps, and it's not uncommon for a cable to become disconnected and no signal to be received if the connector is moved a bit, making the connection less than perfect.
Another drawback is that the HDMi connector usually has a royalty. Therefore, it is very common to see that graphics cards and monitors, not so much televisions, include one or two HDMI ports to satisfy consumers, and then include several DisplayPort connectors, which are a royalty-free connector.
How to connect the computer to the TV via HDMI
If you wonder how to connect the computer to the TV, the HDMI cable is the solution. First you must make sure that your computer has an HDMI output, either normal, mini HDMI or microHDMI. Connect the cable to your PC and then to the television, and go to the input signal corresponding to the connection to which you have connected.
You may need to configure your television if you want to use it as a second screen. To do this, go to the control panel and go to the screen section, locate which screen your television is using and change the settings so that it detects your television as a second screen and adjusts the resolution.
