Take a look behind your home theater system and you’ll see a number of cables used to transmit audio signals and video signals from one device to another. Depending on the system and configuration, you may be using more audio and video cables than you can count on one hand. In a world where it seems more is better, it’s not often that we run across a situation where less is more. Such is the case of the High-Definition Multimedia Interface (HDMI). HDMI is a specification developed by a consortium of 7 leading consumer electronics companies, which include Hitachi, Toshiba, Sony and Philips. It combines both audio and video into a single, compact interface for use with DVD players, digital TV’s, set-top boxes, and other audio and video devices.
The HDMI interface is an all-digital interface, eliminating the signal degradation that occurs in the signal conversion process. A typical audio or video cable is designed to carry an analog signal from one device to another. The audio and video signals generated by a DVD player originate as digital signals. The DVD player must convert the digital signals to analog signals before sending the signals across the cables. Once the analog signals are received, they are then converted back to digital before being processed and displayed as a picture on a screen or heard sonically as music or voice. The analog to digital and digital to analog conversions reduce the integrity of the signal and degrade the quality of the audio and video. HDMI is an all-digital, uncompressed standard, using the original digital signal without the need for signal degrading conversions or compressions.
HDMI supports standard, enhanced, or high-definition video including 720p, 1080i and even upcoming 1080p. Plus HDMI supports standard to multi-channel surround-sound audio with an overall bandwidth of up to 5 gigabits per second. What this means is with HDMI you need only one compact cable for a blazing fast, high-quality audio/video connection.
Endorsed by the major motion picture producers, as well as cable and satellite companies, the HDMI specification includes High Bandwidth Digital Content Protection (HDCP). HDCP is an Intel specification originally developed for use with the Digital Visual Interface (DVI) to protect digital content received by DVI compliant devices. The underlying HDCP technology used in DVI is the basis for the new HDMI specification. For those that have already invested in a DVI equipped device, the video portion of HDMI is fully backwards compatible. Since DVI is strictly a video interface, unlike HDMI that supports both audio and video, a separate connection would be used for the audio signal. If you have a DVI enabled video card in your PC, the good news is that HDMI-enabled devices are backwards compatible with DVI-based PCs, so you can display PC gaming or entertainment content on your HDTV. You can connect a DVI device to a HDMI device by using a DVI to HDMI cable. Or if you already have a DVI cable, you can use a DVI to HDMI adapter.
Michael Weizer is Director of Marketing for Accell Corporation. Accell, a wholly owned subsidiary of BizLinkTechnology, is a member of the HDMI trade organization. Accell is focused on the design, manufacture and delivery of affordable, high quality connectivity products including computer and networking cables, mobile connectivity accessories and audio/video cables and interconnects. For more information, please visit our Web site at www.accellcorp.com .