Stands for "High-Definition Multimedia Interface." HDMI is a digital interface for transmitting audio and video data in a single cable. It is supported by most HDTVs and related components, such as DVD and Blu-ray players, cable boxes, and video game systems.
While other types of A/V connections require separate cables for audio and video data, HDMI carries the audio and video streams together, greatly eliminating cable clutter. For example, a component cable connection requires three cables for video and two for audio, totaling five cables in all. The same information can be transmitted using one HDMI cable.
Because HDMI is a digital connection, HDMI cables are less prone to interference and signal noise than analog cables. Also, since most components, such as DVD players and digital cable boxes process information digitally, using HDMI eliminates the analog to digital conversion other interfaces require. Therefore, HDMI often produces the best quality picture and sound compared to other types of connections.
HDMI cables are typically more expensive than analog cables, largely because they cost more to manufacture. But it is important to remember that with HDMI, you don't need to buy separate audio and video cables. Besides, the single all-purpose connection may alone be worth the difference to those who don't like dealing with confusing cables and connections. Just remember that before you buy an HDMI cable, make sure the devices you are connecting have HDMI connections available.