Jointly developed by Panasonic, Sony, Philips, Hitachi, Silicon Image and Thomson and Toshiba, HDMI has been the driving force behind the Blu-Ray movie players, HD-DVD, high definition TVs (HDTV) and other AV products.



Defining HDMI

HDMI is a cable and plug in device that allows for the delivery of high definition video resolutions and also multiple audio channels.

The HDMI itself is a cable that contains 19 wires inside, which allows for the delivery of 5 Gbps of uncompressed digital audio/video, a bandwidth previously unheard of.

How it Works

The HDMI wires function by emitting digital signals from an AV source, be it an A/V receiver, DVD player, or satellite receiver. It then relays the signal back to another digital device (i.e, a HD camcorder). Despite the high quality of the audio/video, HDMI actually utilizes less than 50% of its bandwidth.

All HDMI wires have 192 khz, 24 bit 8 channels, which allows for transmission of uncompressed audio. However, it also has support for compressed ones, like Dolby and DTS.

Features

Aside from delivering the highest quality AV possible, HDMI also has the capacity to serve up high quality video, from 720p, 1080I and 1080p. Stereo support and multi channel, surround sound are also part of the package. Moreover, it is not limited to definition formats like NTSC, but also allows for formats like PAL and 480p.

There is also an auto lip sync function built in, which permits an HD device (compatible with HDMI 1.3 or higher) to properly align out of sync AV.

HDMI are classified into two: Type A and Type B. Type A is the standard 19 pin cable and is suited for TV, computers, and other HD consumer products. Type B has 29 pins and is geared towards cinemas.

HDMI Advantages and Benefits

The best way to determine the advantage of having an HDMI enabled device is to just look and/or listen to it. Because HDMI is all digital, the data that is delivered is vastly superior to analog devices. Unlike analog cables, there is no compression, so there is no loss of visual or audio detail. Also, unlike other digital interfaces, there is no digital to analog conversion going on, a process that can lead to a deterioration in the data.

Versions

Because it has more bandwidth than it actually uses, progress and innovation of HDMI is made easier. The earliest release HDMI 1.0 came out in 2002 and supported 3.96 Gbps for video and 8 channel LPCM/192 kHz/24-bit for audio. The subsequent releases and updates have added support for One Bit Audio, Deep Color (30bit to 48 bit), Dolby TrueHD and many more.

The biggest advantage of HDMI, cost wise is that with a single HDMI cable, it renders obsolete the need for 3 video connections that used to be needed for HD. In the case of HD audio, six connections were previously needed.

Based on the surveys, over 140 million HDMI devices were sold in 2007 alone, and it is widely expected that the number will increase even more in the upcoming years as prices drop and technological innovations continue.