The HDMI future

In the history of television, broadcasters have always led development — both with their own internal research and development and by persuading manufacturers — to produce the necessary equipment to create, process and transmit video and audio for consumers. However, things have changed — with a vengeance.

In December 2002, a consumer vendors group (comprising Hitachi, Matsushita Electric, Philips Electronics, Silicon Image, Sony, Thomson and Toshiba) announced the base specifications for a new standard called the High-Definition Multimedia Interface (HDMI). Silicon Image was also a member of the group that developed the Digital Visual Interface (DVI).

HDMI was conceived as a standard interface for connecting any piece of equipment operating with uncompressed digital video and audio signals. It replaces the mess of cabling that can often be found in the homes of those who are in tune with modern audio and visual electronics. With a standard connector interface, both digital video and audio can remain in the digital world as they pass in this serial format between different boxes. This also avoids the inevitable degradation of signals as they are converted to analog for interfacing and then reconverted to digital formats in the next piece of equipment.

From day one, the HDMI standard has allowed for up to eight channels of audio and 24-bit 192kHz sampling and has been compatible with all the ATSC HD video standards. Although it has not yet entered the majority of homes, HDMI is the future de facto digital interface system for the consumer vendors.

The original version (1.0) was followed by a working 1.1 standard in May 2004. It was later upgraded to version 1.2 in August 2005 to include features such as one-bit audio. Version 1.3 has now been released, and its vision goes way beyond anything that broadcasters have even dreamt about, let alone considered for implementation. For example:

  • The single-link bandwidth has increased from 165MHz to 340MHz.
  • From the previous support of up to 24 bits of color depth, support has now been added for 30-bit, 36-bit and 48-bit color depths in either RGB or YCbCr.
  • It now supports lossless compressed digital audio formats such as Dolby TrueHD and DTS-HD Master Audio.

Apart from allowing higher resolutions and frame rates way beyond today's consumer needs, the number of colors that will be available has increased to about 16.7 million, more than double the 7 million that the human eye can discern. But the availability of that range makes it possible to finally remove the banding effect that can be so obvious as a color slowly transitions across a display. The HDMI founders call this Deep Color.

The new standard also allows a mini connector to be used in small, personal photo and video devices. And, probably the best news in the whole specification: Automatic lip sync correction is available! Competing audio delay ICs, such as Texas Instruments' TPA5050, will attempt to fill that role.

There are reportedly 400 consumer manufacturers that have adopted HDMI, and analysts predict that 60 million HDMI-equipped devices will ship in 2006. The licensing program for adopters calls for an annual payment of $15,000 plus 15 cents for each shipped product, which reduces to 5 cents if the HDMI logo is clearly displayed on the product. It reduces another cent if you're also paying Intel for its HDCP content protection.

All HDMI 1.3-specified products are backwards compatible with earlier products. And when you plug in a new product, the system automatically configures itself to suit.

Using regular copper cable, long runs can be made, and when I am in the market to replace my analog interfaced equipment, I will certainly go the HDMI way. Maybe then I can take all those RCA cables and turn them into a work of art.

Paul McGoldrick is an industry consultant on the West Coast.

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