HDMI Graphics Card Technology: High-Definition Multimedia Interface Explained

High-Definition Multimedia Interface, or HDMI, is a fully digital format typically used for sending uncompressed digital picture and sound data to a digital display device.

HDMI is a superior alternative to analog technologies such as Video Graphics Array (VGA), composite video, Separate video (s-video), or component video due to its entirely digital format and the amount of data it can send and receive.

Since HDMI signals are uncompressed, there is no loss of signal integrity during the transmission of video or audio information, resulting in crystal clear images and rich sound.

Further, the use of HDMI transmission greatly reduces the total number of cables necessary to send and receive audio and video information, vastly simplifying the process of activating and connecting hardware, and eliminating the jumble of wires that previously tended to manifest behind home theater and computer systems in the past.

As opposed to the older analog image transference protocols, an HDMI signal is able to carry:

And HDMI can carry all of these signals, simultaneously, on a single connection. By grouping all this information into a single cable, HDMI technology allows the connection, integration, and centralized control of the following devices:

As well as most other forms of digital multimedia appliances.


There are presently five different types of HDMI connections, each native to a particular specification of HDMI communication protocols:

HDMI Type A Connection: a 19-pin plug that supports HDTV, EDTV, and SDTV, and is fully compatible with DVI-D.

HDMI Type B Connection: a 29-pin plug that doubles the output of Type A (this technology is not yet widely available).

HDMI Type C Connection: a mini-HDMI connector designed specifically for handheld or portable HDMI devices.

HDMI Type D Connection: a micro-connector that maintains the same 19-pin format as Type A and Type C, but miniaturizes the connection plug to the size of a Universal Serial Bus (USB) adapter.

HDMI Type E Connection: specifically designed for use in automotive connections.

Further Specification definitions can be researched as follows:

DVI Compatibility

HDMI video is fully backwards-compatible with Digital Visual Interface (DVI) technology with the use of an HDMI-to-DVI connector. Since both HDMI and DVI are non-compressed digital communication protocols, no signal loss or quality degradation occurs when implementing any form of HDMI-to-DVI translation or adaptation.

This full compatibility allows users with high-end graphics cards that contain a DVI-out port to connect to any HDMI appliance or display device with the use a simple connector.

It should be noted that while no signal loss occurs at the point of translation, HDMI cables longer than 15 feet have been known to lead to some forms of interference - for this reason, cables shorter than this length should be implemented whenever possible, especially when translating to or from DVI devices.

The CEA-861 Protocol

The basic communications protocol utilized by HDMI is called CEA-861. The second iteration of this protocol, CEA-861-B, was developed by the Consumer Electronics Association in 2002 as a generic digital communication language for digital devices. CEA-861-E has been in existence since early 2008, and is now the industry standard for communication between digital devices.

Since HDMI is built on this generic, industry-wide digital language, HDMI enjoys almost universal compatibility with all forms of digital hardware available on the market, making it one of the most versatile and widely-used communications formats ever devised.

HDMI Bandwidth

Obviously, carrying all this information simultaneously down a single cable means that the available bandwidth of a digital HDMI connection far exceeds any of its analog predecessors.

Available HDMI bandwidth caps out at nearly 5 gigabytes per second, and this maximum bandwidth cap is more than double the bandwidth needed to send all the information currently carried by the HDMI signal. This means that HDMI improvements in the future will not be in danger of exceeding the maximum bandwidth cap for some time.

In short, HDMI can be augmented to nearly twice its present functionality and information distribution capacity before the format even approaches obsolescence.

CEC connection

Another feature of HDMI is the Consumer Electronics Control (CEC) connection. This feature allows the user to integrate and centrally control two or more CEC-enabled appliances that share an HDMI connection.

This allows users to program a single remote control, or other control device, to manage and operate all HDMI devices connected to the local HDMI nexus.

HDMI Graphics Cards

Some newer graphics cards are equipped with HDMI-out, which allows the user to plug the computer system into other HDMI compatible devices.

This allows HDMI compatible graphics cards to stream movies or games to a large HDMI digital display device, such as a widescreen HDTV. Since HDTVs outsize any monitors available on the market, many gamers jump at the chance to utilize HDMI technology and broaden their gaming experience to previously unattainable proportions.