Guide in Buying HDTV
I wrote this article originally for the HDTVetc magazine for the August 2003 issue, and it was later published on the HDTV Magazine in 2006. Consumers still go through the same struggle at national-chain stores today. I updated the article to include current HD equipment and technologies. Its tutorial substance and analysis are still applicable today, and are intended to help consumers in making the right purchasing decisions. Enjoy the reading. The following topics are covered in this segment: H/DTV and NTSC TV Systems, What are they? The First Effort of the DTV Transition Quality HDTV, or Quantity DTV, or Both? Backward Compatibility with Legacy Analog TV for Digital Broadcast Satellite/Cable, and the DTV Transition Tuner Integration The Effect DVD had for DTV The Rush for Knowledge You have been hearing about HDTV and decided to start looking for one.
A friend of yours reminds you that the general knowledge about buying regular TVs from the CRT analog era is not sufficient to select a digital product today, so you quickly review what you read about widescreen, black bars, digital tuners and resolution, and hope things would clear out at the store. You get into the typical nationwide consumer electronic store most people go to, and suddenly see several dozens of HDTV demo sets staring back at you. A salesperson is approaching you, the person's face is familiar; the salesperson is the one that sold you the new dishwasher two weeks ago; now the person is selling HDTVs with authority. At that point you start feeling worried, but you hang in there. Obviously this store is not a quality dedicated A/V retail place.
Many consumers make their purchases based on the uninformed advice of untrained staff from typical nationwide consumer electronic chains. In the near past, a typical store could only have one of those HDTVs actually displaying HD, the only one that had an HD tuner; the rest were showing the same image from a video distribution loop not suitable for HD quality. Today perhaps the whole store feed is all HD, and the sets that are staring at you show the same picture, but with different colors, contrast, image enhancements, blacks, whites, etc. because no one bothered to set them correctly. So you start wondering why HDTV is not consistently perfect as is being preached, is that what HDTV is about? The sales person turns toward you and, in the middle of your consumer panic attack, tells you: "trust me, buy this TV, it would look much better at home once connected to an HD tuner". Would you buy a car without test-driving it? Millions of people went through similar experiences since HDTV was introduced in November 1998. Fortunately, some improvement is gradually seen in the stores, especially in dedicated A/V retail stores, which should take more time to help consumers understand the concepts behind each display technology, and not just quickly sell the HDTV inventory with the red tags, as most national consumer electronic chains do. Most consumers love red tag savings, and many leave the stores wallet-happy with a product they do not understand. Perhaps many of those do not actually want to understand because the HDTV technology has been introduced with a complexity level they refuse to deal with to just get a TV. To illustrate the complexity of an HDTV purchase decision you might want to read Is HDTV Complex Enough? The objective of the article you are reading is to help you make your purchase with more confidence, but first allow me to cover the following basic subjects about HDTV: H/DTV and NTSC TV Systems, What are they? You might already know of the US plan to replace our current analog interlaced TV system (NTSC) dated from the 1940's by a digital DTV system, by February 17, 2009.
Curiously enough the idea started as "analog" HDTV until General Instruments proposed an all-digital system in 1990. The DTV standard is composed of 18 digital formats grouped into two levels of quality, as approved by the ATSC (American Television Systems Committee) in 1995: 1) SD: Standard Definition, with 480i/p (i:interlaced, p:progressive) viewable horizontal lines of vertical resolution (rows counted from top to bottom), each line with up to 704 total pixels of horizontal resolution (counted from left to right), and with an aspect ratio (relation of width to height in units) of 4x3 (as regular TV), or widescreen 16x9. 2) HD: High Definition, with 720p and 1080i/p viewable horizontal lines of vertical resolution (rows counted from top to bottom), each line with respectively 1280 (for 720p) or 1920 (for 1080i/p) total pixels of horizontal resolution (counted from left to right), and only in widescreen 16x9 aspect ratio. Note that, because is not complex enough, the horizontal lines (rows) are expressed as "vertical" resolution (480, 720, 1080), and the vertical columns made of the aligned pixels on the horizontal lines are expressed as "horizontal" resolution (704, 1280, 1920). DTV was 15 years in the making before it went on the air in November 1998. HDTV is the quality part of DTV, but its implementation is not mandatory, SD is. I will use the term DTV only when addressing the digital TV system in general. Later in 2000, the Consumer Electronics Association (CEA), allegedly to help confused consumers, created another resolution level in between: ED (enhanced definition). This promoted the 480p SD format to ED level, leaving only the 480i format in the SD level. It also granted any TV the right to be labeled HDTV if capable to display only 810i lines of vertical resolution within the displayed image, rather than 1080i.
One can argue how much this intervention from the CEA helped consumers more than helped manufacturers getting rid of mediocre sets. But that was back when CRT based DTV sets were the strength of the market; now most DTV sets are fixed pixel displays and their resolution is clearly specified as a pixel count in both directions. Our current NTSC over-the-air (OTA) TV system is 480i analog interlaced (actually 525i with 480i viewable horizontal lines of vertical resolution). The regular channels of digital satellite and digital cable could be compared to digital SD of broadcast DTV, but they are also transmitting dozens of channels in HDTV. To facilitate the transition, broadcasters were given one extra channel slot from the FCC for the simultaneous broadcasting of the analog and digital versions of their programming. It is a large investment for TV stations to build a DTV facility with new cameras, production, equipment, etc. When DTV is fully implemented, broadcasters have to return one of the two channels, analog over-the-air broadcasting will stop, and current analog TVs, VCRs, TiVos with analog tuners would stop "tuning" as well (but they will still work as display devices if fed with a 480i analog signal from a converter, VHS tape, DVD player, etc). This date was originally set for January 2007 but has been extended to February 17, 2009. Once DTV is implemented, the FCC will auction that spectrum of airwaves. Most OTA terrestrial TV stations are already broadcasting DTV in SD and HD widescreen, and consumers are buying HDTV sets at accelerated pace every year.
The First Effort of the DTV Transition Just a look back at CEA's 2003 statistics, on the first 5 years of HDTV approximately 6 million DTVs (of which only 300,000 where integrated with DTV tuners) and 400,000 tuner set-top-boxes (STBs), were sold between 1999 and 2003. By the end of 2007, the HDTV count was 8 times fold, and about 50% of households have digital TV sets, according to the CEA. Back in 1998/9 it was not unusual for first generation HDTV monitors to cost $10,000, and HD STB tuners to cost from $700 to $3,000. It was expensive for early adopters. By the end of 2007, a huge variety in technologies and TV sets was available for every viewing environment. DTV sets are much better in quality, and sell for a small fraction of the price they sold back in 1998. Quality HDTV, or Quantity DTV, or Both? We all love the incredible video quality of HD, however, since HD is not mandated within the DTV plan, it allows a broadcasting station to use the allotted 6 MHz space (for the HD channel), to multicast instead several sub-channels of lower SD quality, as it is actually happening on many stations across the US. When sharing the same 6MHz total bandwidth, SD sub-channels rob about 2-3 Mbps each from the needed bandwidth of an HD channel that by itself should broadcast at 19.4 Mbps (if the station also multicasts an HD sub-channel).