1080p HDTV Sets are flying off store shelves... Should you opt for One?

Way back in 2007, the ECA (Electronics Consumer Association) had estimated that there were more than 60.6 million HDTV sets in U.S. households.

This represented an HD penetration of 36% among all U.S. households. Equally important, a third of these HD households had multiple HDTV sets; in most cases, the second or third HDTV set was a 1080p television.

A lot has changed since then in the field of HDTV sets and the number of 1080p HDTVs have surpassed 720p TVs to the point that 1080p sets at anything above and including 40-inch screens, have become the 'de facto' standard. 

It is the drastic fall in prices of HDTV sets we have seen during the last two years that has led to a sharp increase in the presence of HDTVs, and in particular of 1080p televisions.

This despite the higher price tag and equally important, the non-availability of broadcast programming in 1080p! In fact, the only commercially available 1080p video content comes in the form of high-definition discs from Blu-ray.

The irony is that notwithstanding the increase in the presence of HDTV sets in US households, there is still a lot of consumer confusion about high definition television.

During these last years, surveys have constantly shown that having an HDTV set in the house does not necessarily imply the consumer has an understanding of HDTV technology. The lack of consumer understanding in this area is such that many HDTV owners do not even know if they are watching HD programming or not!

The unfortunate thing is that TV makers and retailers alike seem to have taken a ride over this lack of consumer understanding. They have pushed ahead the more expensive 1080p HD sets even at screen sizes where difference in picture detail between a 720p and a 1080p image is unperceivable.

There is a very simple reason for this drive by TV makers and retailers - 1080p sets carry a higher price tag and yes... a higher profit margin. Mind you, higher prices does not necessarily mean higher profits. But in the case of HDTVs, the production costs associated with 1080p HDTVs are only marginally higher than those of 720p sets and significantly less than what the average retail price difference between 720p and 1080p sets seems to imply.

To justify this move, TV makers and retailers alike profess to the world that 1080p HDTV sets deliver better resolution than 720p HDTVs and improved performance over 1080i. In addition, 1080p sets are often bundled with a more appealing feature set - irrespective of whether these features are of any use in everyday viewing - to help these 1080p HDTV sets sell at an even higher price!

The average TV consumer does not have an understanding of the differences between the different HDTV formats, and therefore is ready to pay the higher price tag associated with 1080p HDTVs to get the 'better TV'.

It is true that a 1080p HDTV delivers improved picture resolution, but...

	Does this additional picture detail afforded by 1080p sets always imply a better picture than a 720p HDTV?
	And how does 1080i relates to 1080p when it comes to picture performance?

 

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June 2009: Worth taking note that...

This article was originally published in mid-2005 when the first 1080p HDTV sets started to appear on store shelves; it was then revised later in May 2006. It was a time when you had to spend anything between $1000 and $1500 to make the jump to what represents the gold standard in HDTV. And this to get a 1080p HDTV that in most cases did not even support a 1080p input!

Technology has changed a lot since then. Not only all present HDTVs - irrespective of format - support 1080p input,   HDTV sets have become much better, bigger, and equally important, significantly cheaper - cheaper to the point that what once represented the unattained dream for the average home theater enthusiast, has now become a rather common reality.

And what started as 1080i vs. 1080p is now 720p vs. 1080p; rather in most case, it is just 1080p because 720p sets have become a minority in most manufactures' HDTV lineups.

This new updated article reflects this changing environment in the HDTV world.

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HDTV Formats: It is all an issue of 'Image Resolution'

There are currently a number of different HDTV formats as adopted by the Advanced Television Systems Committee (ATSC), based on 720p, 1080i, and 1080p - using refresh rates that vary between 24 Hz and 60 Hz.

The basic difference between these HDTV formats is mainly one of image resolution. The 720p is on the lower-end of the scale with an image resolution of 1280 pixels by 720 lines. The other two formats both support 1920 pixels horizontally by 1080 lines vertically.

In other words, both 1080p and 1080i support the same theoretical image resolution. However, there is a significant difference in the way the 1080i (interlaced) and the 1080p (progressive) formats build up the image.

Image resolution in fixed-pixel displays is a very HOT topic with many HDTV buyers. For many, the obvious choice is to opt for the latest 1080p HDTV - also referred to as ultra-HD, full-HD or higher HD by some manufacturers. But as expected, there is a price to pay to get the latest in HDTV technology.

On the other hand, the way interlaced 1080i and progressive 720p formats build up the image may render the lower resolution 720p format more suitable to display certain image content than the higher 1080i format.

So... do not simply jump to the conclusion as to which HD format is best; each of these formats has its strengths and weaknesses.

1080i HDTV

Up to a few years ago, this was considered as the reference standard in HDTV. Nearly all first-generation HDTVs were rear-projection sets that supported this standard. This format boasts a picture resolution of 1920 pixels by 1080 horizontal lines that are painted on the screen in two interlaced halves (hence the 'i' in the '1080i' format). It first paints all 540 even-numbered lines on the screen (referred to as the even-field), and then proceed with the painting of all 540 odd-numbered lines (or odd-field). These two fields together form a single image frame of 1080 lines.

This process is repeated 60 times per second - each time painting only half of the lines per frame. This means that the entire image is painted on the screen in two separate passes, 30 times every second.

Because of the way the interlaced process paints the screen, all picture information contained in adjacent odd and even lines in an interlaced image is 1/60^th of a second out-of-synch with the next or previous line. The image difference between the two halves of the picture would show up in what are referred to as 'interlaced artifacts'. Not much of an issue with slow-moving or static content, but these artifacts would become more pronounced with fast moving objects. This in itself will impact on the type of image content that is best viewed on an interlaced display.

720p and 1080p HDTV

In contrast, all progressive-scan formats - 480p (Enhanced-DTV), 720p high definition TV, and 1080p HDTV - display each individual line sequentially in a single pass to build up the complete frame. This means that in progressive scan video, image information between adjacent lines is displayed in a 'more correct, timely manner'. This makes progressive scan capable of delivering a smoother, cleaner image, especially with sports and other motion-intensive content.

Effective Resolution: 720p, 1080i, 1080p - Which is Better?

720p vs. 1080i

TV stations would normally broadcast only in either 720p or 1080i but not both; the predominant format is 1080i. This in itself is not an issue; all present HDTV sets can display pictures in any HDTV format by up-converting or down-converting to the set native format, i.e. the one in which the set is designed to produce a picture.

Theoretically, from a pixel-count perspective, 1080i supports better spatial resolution than a 720p HDTV. In fact, 1080i supports a pixel count of over 2 million pixels as against the 0.92 million pixels supported by 720p HDTV but...

In reality the situation is somewhat different when it comes to an interlaced format. As expressed earlier on, the differences between the two halves of an interlaced image lead to interlaced artifacts. In order to reduce the visibility of these artifacts, the vertical resolution of an interlaced signal has to be filtered. That reduces the real image vertical resolution far below the number of scan lines (typically 60% of the number of lines) associated with the interlaced format. Furthermore, 1080i material is limited to around 1440 pixels horizontally; this reduces the overall effective resolution of the 1080i format to around 0.93 million pixels.

It is thus clear that the actual difference in effective resolution between 720p and 1080i is almost negligible. And this apart from the fact that a 720p display is capable of a better flicker-free picture when dealing with fast moving action movie scenes and sports.

Yet there is another issue against interlaced video, that of digital compression of images. Digital image compression is more efficient with progressive video at the source than interlaced video. High definition digital TV broadcast uses the same 6MHz maximum allocated broadcast bandwidth as with standard definition analog TV. This means that it is necessary to apply compression to make high definition images fit into the space allocated for a broadcasting TV channel. 

And what about 1080p HDTV?

The situation with 1080p HDTV is totally different. The horizontal resolution of 1080p HDTV content is equal to the number of scan lines since there is no need to reduce this as in the case of interlaced material. This means that 1080p supports the full 2.07 million pixels (1920 x 1080 pixels), as against the effective 0.93 million pixels in 1080i video and 0.92 million in 720p HDTV. And this apart from the added advantage that 1080p enjoys over 1080i in that all 1080 lines are displayed in a single pass.

In other words, 1080p HDTV enjoys the best of both worlds - it has the spatial resolution of 1080i HDTV material and the smooth stable image of a progressive scan format. It is a case where if you want the very best in high definition television, then 1080p HDTV is the way to go, but...

As things stand today, there is no 1080p HDTV broadcast and there is little chance that broadcasters will jump to 1080p any time soon due to bandwidth limitations. Even high-definition games on the Xbox 360 and PlayStation 3 are usually 720p, though the user can upscale these to 1080i or 1080p in the console user settings. The only way you can get hold of true 1080p HDTV commercially available content - apart from hooking your PC to your HDTV set, is via an HD disc - using a Blu-ray player. The large majority of high definition discs are natively encoded in 1080p while all the latest high definition players support 1080p output.

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Apart from CRT, interlaced formats are not an option with fixed-pixel displays, namely microdisplay based DLP and LCD rear-projection systems as well as plasma and LCD flat-panel sets. All microdisplay based TVs are essentially progressive-scan technologies, so when presented with interlaced video (480i or 1080i), they convert it to progressive-scan for display. This explains why manufacturers are shifting away from 1080i and instead moving directly from 720p to 1080p HDTV.

Yet there is another important issue here and that is specific to all fixed-pixel displays. These displays will have to convert incoming video - irrespective of format or resolution, to the screen native resolution. The process involves upconverting or downconverting the video resolution to match that of the display; in the case of interlaced video, it also involves deinterlacing. These processes can introduce errors that are often overlooked by HDTV buyers despite that these may impact picture quality.

Unfortunately, how well an HDTV set scales an image or deinterlace video content is  not something one can put in the set specifications list.

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1080p HDTV Sets have become readily available but... what about 720p sets?

As already indicated earlier on in this article, 1080p HDTV sets have become more widely available than their 720p counterparts as manufactures are mainly focusing their TV line-ups on 1080p sets. In particular, this is true with LCD HDTVs where major TV makers have shifted almost completely away from 720p HDTVs for anything larger than 32-inch.

In other words, if you want to enjoy a price advantage at the larger 40-inch to 50-inch screen sizes, your only present option is a plasma TV. The price difference between a 50-inch 720p set and a corresponding 50-inch plasma 1080p HDTV hovers between $250 and $400.
This is the price difference between the Samsung 720p PN50B450 50-inch plasma HDTV and its corresponding 50-inch Samsung 1080p PN50B550 plasma TV from within the 2009 Samsung HDTV lineup. This difference would be seen even more pronounced when one considers that the 720p HDTV is selling online at under $1000. In other words, the price difference is more than 26%
	You will find that there is a similar price difference if you were to look at Panasonic plasma HDTVs. Panasonic extremely popular and equally affordable 50-inch TC-P50X1 720p plasma HDTV is selling at just under $900 while its 1080p equivalent, the 50-inch Panasonic TC-P50S1 is selling online at around $1,200.

 

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The Bottom Line: Should you opt for a 1080p HDTV... if a 720p version is available?

When is a 1080p TV worth the extra expense? Well, there is no straight answer here. It all depends on what are your requirements, yet there are a few facts you should know before making any decision:

	Image Detail: It is true that these sets are capable of producing spectacular results with ultra sharp images. But it is extremely unlikely that you will be able to see any difference in image detail when viewing broadcast 1080i content over a 720p television as against a 1080p HDTV set - especially on the smaller sets. This in view of the limitations associated with the 1080i format as further detailed earlier on.
	Viewing Distance: Surely, you will not perceive any difference in image detail between 720p and 1080i content on anything less than and including 50-inch 1080p sets from 10 feet away. You would need to go really big for the extra image resolution to make any difference. You will also have to sit closer than twice the screen width - even at 1.5 times, and feed your 1080p HDTV set with a good quality 1080p encoded source to start seeing any difference. More on TV viewing distance can be found in our guide here.
	Availability of 1080p Content:  Keep in mind that at present, apart from HD discs, true 1080p HDTV encoded material is almost non-existent. What's more, none of the major networks has announced 1080p broadcasts - and it is unlikely that they will make such a move in the near future considering the bandwidth requirements.

 

Nevertheless, the whole equation in favor of 1080p HDTV sets is changing fast. The present marginal difference in price between 720p and 1080p HDTV sets has already made  1080p HDTV sets more of a real option - especially if you want to have the latest and best spec in HDTV.

And the 1080p option would make even more sense if you plan to go really big. Consider a 1080p HDTV for anything bigger than 52-inch - especially if you have a good quality 1080i or 1080p HD source and plan to sit closer to your TV than twice the screen width.

Similarly, go for a 1080p HDTV if you plan to use your TV as a big computer monitor. Though icons and text may appear too small on a 1080p TV, and you may have to re-scale the desktop to fit, yet a 1080p set gives you some added flexibility when it comes to computer connectivity.

If none of these issues represent a priority, or are working on a tight budget, then you may very well do your bank account a favor and get a 720p HDTV if available within the screen size category you are looking for; high definition content will still look great!