What Does HDMI Stand for? Here's How HDMI Works

At its core, HDMI is a proprietary audio and video interface for transmitting uncompressed video and audio streams between compatible devices. It serves as a digital replacement for earlier analog standards, such as video graphic array (VGA) and component video.

Manufacturers debuted the first HDMI version (HDMI 1.0) in 2002. Since then, there have been nearly a dozen revisions, including the following key updates:

The HDMI interface consolidates video transmission, audio output and other data into a single cable. This not only simplifies things but also makes transmitting high-quality audio possible, making for a higher-quality viewing and listening experience overall.

A group of electronics manufacturers created the HDMI standard as a set of guidelines for creating high-bandwidth connections between digital devices. With the right setup, HDMI can make a significant difference in a home-theater system.

HDMI and 8K

The current standard (HDMI 2.1) can transmit up to 48 gigabytes per second and easily supports 8K (7,680 x 4,320 pixels) or 4K (3,840 x 2,160 pixels) resolutions with much higher refresh rates than the original HD (1,920 x 1,080 pixels).

For example, you can watch at 8K resolution at a refresh rate of 60Hz, or you can watch at 4K resolution with a refresh rate of 120Hz for your perfect balance of crystal-clear video and super-smooth action.

HDMI can cut down on the number of cables required to connect components, and it can even reduce the number of remote controls you need to watch a movie.

HDMI connectors come in various types to accommodate different devices and usage scenarios. Each type caters to specific device categories, from standard consumer electronics to portable devices.

There are different HDMI cable types that correspond to the different types of HDMI connectors. The five primary HDMI connector types include:

HDMI cables support a range of features and capabilities, such as:

You'll find HDMI across a broad spectrum of devices and uses, including in portable devices like smartphones, tablets and laptops. Here, HDMI ports make it possible for you to watch a video on an external display.

For example, maybe you want to stream a movie on your laptop but watch it on your desktop monitor. To do this, you'll need to connect the two with an HDMI cable.

Similarly, a standard HDMI cable or a high-speed HDMI cable is now integral to most home entertainment systems, connecting Blu-ray players, streaming devices, video game consoles and ultra-HD TVs.

Outside the home, you'll find the use of HDMI in professional audiovisual settings, supporting video transmission in commercial displays, projectors and conference room setups.

HDMI technology and high-definition televisions are now ubiquitous, but that wasn't always the case.

Before the development of HDTVs, most TVs displayed pictures in what people refer to as standard definition. The picture was roughly square, with an aspect ratio of 4:3. Its resolution, or the number of dots that make up the picture on the screen, was about 704 x 480 pixels.

In standard definition, each piece of a moving image was really half a picture, but the pictures changed quickly enough that a human brain didn't really notice. These older TVs relied on analog signals, which travel as a constantly varying electrical current.

In contrast to standard-definition TVs, HDTVs are digital. They use information in the form of ones and zeros. This information travels through cables as distinct electrical pulses.

HDTVs have an aspect ratio of 16:9, so the picture is more rectangular. They have a higher resolution as well: Current HDTV standards allow for resolutions of up to 1920 x 1080 pixels.

HDTV signals can also be progressive, meaning that the each frame of the moving image is a whole picture, rather than half of one.

­So, compared to standard TVs, HDTVs have a wider screen, more pixels and a faster refresh rate.

Often, HDTVs can display more colors than older sets. This means that HDTVs need more data and need it a lot faster than standard-definition TVs do. If an HDTV can receive this information digitally, it also doesn't have to spend time or processing power converting the signal from an analog format.

Since its inception, HDMI has undergone several revisions to keep pace with advancing technologies. The HDMI Forum, responsible for HDMI specification development, continually updates standards to support emerging trends such as 8K resolution, high dynamic range (HDR) and enhanced gaming features.

Looking ahead, this type of digital interface is poised to remain the de facto standard for high-quality audiovisual connectivity, ensuring seamless integration across a myriad of devices and applications.

As consumer electronics continue to evolve, HDMI will no doubt continue to adapt so that people can continue to enjoy compatibility among their many devices and systems.­

We created this article in conjunction with AI technology, then made sure it was fact-checked and edited by a HowStuffWorks editor.