What Does HDTV Stand For?

The digital signals used by HDTV aren't prone to static like those of analog television.

HDTV is the acronym for High-Definition television. HD has 1 to 2 million pixels per frame, which is nearly five times the amount of pixels as that of Standard Definition -- SD -- television. HD was made available in the United States in the early 1990s shortly after its debut in most European countries. The perks of HDTV included digital surround-sound and the ability to play movies in their original widescreen format. Now that the format is becoming more and more noted among and available to the general public, HDTV has gained much attention. But what is it that really sets HDTV apart from SD television?

Video Compression

HDTV is digitally broadcast using video compression. HDTV compression is what makes large quantities of information small enough to transmit in quantity. The HDTV image has twice the luminance definition and is 25 percent wider than SD television. The clarity in picture is the biggest factor to understanding the difference in HDTV. The difference in quality of sound is also dramatic because the pictures are accompanied by multi-channel, CD-quality sound. The HD broadcast systems are identified by three major parameters: frame size, scanning system and frame rate.

Tech Specs of HDTV

DTV is the transmission of pure digital signals and the display and reception of those signals on a digital TV set.

Analog signals are transmitted through a process similar to radio transmission. HDTV represents the highest level of quality available in the class of digital television. Although all HDTVs are digital, not all digital TVs are HD. Analog TV sets have 525 scan lines while HDTV has either 720 or 1,080 scan lines of resolution. Each additional scan line translates into a much sharper picture, resulting in film-like quality.

Viewing HDTV

Depending on the quality of your television, other equipment may be needed to view HD television. An HD-ready television set is sufficient if viewing in the United States as these sets can display HD content without using an external box. High-definition image sources are vast, including terrestrial broadcast, direct broadcast satellite, digital cable, IPTV, the high definition Blu-ray video disc, internet downloads, the Blu-ray disc compatible Sony PlayStation 3 video game console and the Microsoft Xbox 360 video game console.

HDTV Color Support

There is no standard for HDTV color support. Until recently, the color of each pixel was regulated by three 8-bit color values, each representing the level of red, blue and green which defined a pixel color. Together, the 24 total bits defining color yielded just under 17 million possible pixel colors. Presently, manufacturers have produced systems that can employ 10 bits for each color -- 30 bits total. This provides for a palette of 1 billion colors and a much richer picture.

References

• Hidefster: HDTV - The Tech Specs
• EBU - Tech: HD Image Formats for Image Production