HDTV Standards

There are several HDTV standards. The high definition standards cover such things as the aspect ratio (which is 16:9 for HDTV), the resolution (the number of horizontal lines that make up the picture), the frame rate (which is the number of times the series of still pictures that make up a video image is drawn per second), the way the individual pictures are drawn (interlaced or progressive; with interlaced the odd number lines are drawn for one frame and then the even numbered lines are drawn on the next frame, then the odd, then the even, etc; with progressive all lines are drawn for each frame). The sound quality (which is the Dolby Digital 5.1 standard).

The standards are distinguished by the resolution, the Frame Rate, and whether the picture is drawn in an interlaced or progressive manner. So the HDTV standard with 1080 horizontal lines of resolution, which displays frames progressively, at a frame rate of 30 frame rate per second is properly noted as 1080p30. Usually, the Frame Rate is omitted, so you see it noted as 1080p. This wouldn't be a big deal except that there are 3 different frame rates 24 (the film camera rate), 30 (the video frame rate) and 60 (the video frame rate of an interlaced signal), which come into play when discussing HDTV.

Like everything else in technology the king of the hill is always a moving target. Currently, the top HDTV format in a commercially available TV set is 1080p; the current frame rate is at 30 frames per second. Progressive scanning is considered superior to interlaced scanning because there is less jitter (image artifacts) with fast moving images. Expect to pay a $1000 to $1500 premium to have a 1080p television.

Moving down the HDTV standards, you will find the 1080i standard (that is 1080 lines of resolution with interlaced scanning), 720p, (720 lines of resolution, progressive scan), and finally 720i. Currently, the only products that can provide a 1080p source are Blu-ray Disc and HD- DVD players and computers. The top-tier satellite and cable provider are capable of providing you with the 1080i standard broadcasts on a handful of the hundred plus channels they offer. If you change your TV every 2-3 years then the extra cost of a 1080p set may not be worth the expense. But if you are like most people and change your set less frequently, a set with 1080p capability is a sound investment.