720p vs. 1080p HDTVs: 2009 update

A few years ago I wrote a column about HDTV resolution and whether you should just buy a "standard" 720p/1080i set or pay the extra bucks for a higher-resolution 1080p set. The column was very popular, but people wanted me to update it as the market for HDTVs changed. So I did. The new column was called 720p vs. 1080p: The final word. Alas, it was probably a poor title, because folks asked me to update that one as well.

Eventually, of course, manufacturers will completely phase out 720p TVs. But it may take a few years. While the number of new 720p models is dwindling, several manufacturers, including Sony, Samsung, LG, and Panasonic, are putting out entry-level lines in 2009 that feature 720p TVs and we're getting a lot of readers asking whether they should save some dough and buy them. With that in mind, here's the word on 720p vs. 1080p, updated for this year.

1. What's so great about 1080p?

1080p resolution--which equates to 1,920x1080 pixels--is the current Holy Grail of HDTV resolution. That's because most 1080p HDTVs are capable of displaying every pixel of the highest-resolution HD broadcasts. They offer more than twice the resolution of step-down models, which are typically 1,366x768, 1,280x720, or 1,024x768. These days, HDTVs with any of those three of lower resolutions are typically called "720p." Nobody wants to remember all those numbers, and "768p" doesn't really roll off the tongue.

2. How much extra does a 1080p TV cost?

When I wrote my original article a few years ago, you had to pay a premium of about $1,000 to get a 1080p model at the same screen size as a "720p" set. While the gap has certainly narrowed, there's still a notable difference. In the case of a 32-inch LCD, for instance, you're looking at around a $200-$250 price bump. For example, the Samsung LN32B360 goes for $549.99, while the step-up 1080p version, the LN32B530, goes for $799.99. Sony has a similar price delta when it comes to its 32-inch LCDs.

As you move up the LCD-size chain, your 720p options basically disappear. Samsung and Sony, the two biggest names in LCD, don't even produce 720p LCDs larger than 32 inches anymore. You can still find older big-screen 720p models, like the 40-inch Samsung LN40A450, but they're becoming a rare breed.

When it comes to plasma, Panasonic's entry-level 42-inch TC-P42X1 720p carries a price of around $899.99, while the step-up 1080p version, the TC-P42S1, come in at $1,199.99 (street prices will vary, of course). Move up to Panasonic's 50-inch models and you're looking at more like a $700 delta, with the 720p TC-P50X1 coming in around $1,000 and the TC-P50S1 selling for $1,700--though Panasonic's S1 series does feature more-efficient, higher-contrast NEO-PDP panels. (Note: We do expect prices to drop slightly on all these models as the year progresses).

3. Why is 1080p theoretically better than 1080i?

1080i, the former king of the HDTV hill, actually boasts an identical 1,920x1,080 resolution, but conveys the images in an interlaced format (the i in 1080i). In a tube-based television, otherwise known as a CRT, 1080i sources get "painted" on the screen sequentially: the odd-numbered lines of resolution appear on your screen first, followed by the even-numbered lines--all within 1/30 of a second. Progressive-scan formats such as 480p, 720p, and 1080p convey all of the lines of resolution sequentially in a single pass, which makes for a smoother, cleaner image, especially with sports and other motion-intensive content.

4. What content is available in 1080p?

Today's high-def broadcasts are done in either 1080i or 720p, and there's little or no chance they'll jump to 1080p any time soon, because of bandwidth issues. Dish Networks, Direct TV, and other cable and satellite providers are starting to offer 1080p content on demand, but it's worth noting that the bitrate is not as high as Blu-ray's, so there's some video-compression magic at work.

As for gaming, Xbox 360 and the PlayStation 3 games are usually 720p native, though some titles are being offered in 1080p resolution (also, the 720p titles can be upscaled to 1080i or 1080p in the user settings of those consoles).

Really, the main way to get true 1080p output--aside from hooking your PC to your HDTV--is to get a Blu-ray player (yes, HD DVD players are another potential route, but Toshiba killed HD DVD last year). All Blu-ray players support 1080p output, and--more importantly--the vast majority of discs are natively encoded at 1080p.

5. What kinds of TV technologies offer 1080p resolution?

Aside from CRT (tube) TVs, which have been basically discontinued, everything comes in 1080p versions. That means you can find 1080p-capable versions utilizing all fixed-pixel technologies, including what's left of microdisplays (DLP, LCoS, and LCD rear-projection/front-projection) and flat-panels (plasma and LCD). Of course, as specified above, more affordable entry-level models are still limited to 720p resolution. But whatever the resolution, all fixed-pixel (non-CRT) TVs are essentially progressive-scan technologies, so when the incoming source is interlaced (1080i, or even good old-fashioned 480i standard-definition), they convert it to progressive-scan for display.

At this point, I could just expand on that last point and specify that all fixed-pixel display TVs--all microdisplay rear-projection and all flat-panels--always display everything at their native resolution, which is all they can display. On a 720p TV, that means that all incoming video is displayed at 720p (or 768p, as the case may be); on a 1080p TV, all incoming video is displayed at 1080p. The process of converting resolution is called scaling--sometimes called upconverting or downconverting. A related factor is de-interlacing (see point number 8, below). How well a TV does or does not handle both of these processes is a big factor in how desirable it is--and something that casual shoppers often overlook, since, compared to the screen size or resolution, it's not as easy to show as a spec sheet bullet point.

I should probably put that whole previous paragraph in bold, though, because the message never seems to get through. So, at the risk of overkill, let's restate it with specific resolutions:

6. What happens when you feed a 1080i signal to a 720p TV?

The 1080i signal is scaled, or downconverted, to 720p. Nearly all recent HDTVs are able to do this.

7. What happens when you feed a 1080p signal to 720p TV?

Assuming the TV can accept a 1080p signal, it will be scaled to 720p. But that caveat is important: many older 720p HDTVs--and yes, even some older 1080p models--cannot even accept 1080p signals at all, in which case you'll get a blank screen. Thankfully, most newer HDTVs can accept 1080p signals.

8. What happens when you feed a 1080i signal to a 1080p TV?

It's converted to 1080p with no resolution conversion. Instead, the 1080i signal is "de-interlaced" for display in 1080p. Some HDTVs do a better job of this de-interlacing process than others, but usually the artifacts caused by improper de-interlacing are difficult for most viewers to spot.

9. Side by side, how do 720p and 1080p TVs match up in head-to-head tests?

We spend a lot of time looking at a variety of source material on a variety of TVs in our video lab here at CNET's offices in New York. When I wrote my original article over three years ago, many 1080p TVs weren't as sharp as they claimed to be on paper. By that, I mean a lot of older 1080p sets couldn't necessarily display all 2 million-plus pixels in the real world--technically, speaking, they couldn't "resolve" every line of a 1080i or 1080p test pattern.

That's changed in the last few years. Virtually all 1080p sets are now capable of fully resolving 1080i and 1080p material, though not every 1080p TV is created equal. As our resident video guru, Senior Editor David Katzmaier explains in his HDTV resolutions feature, Blu-ray serves up another video format, 1080p/24, and not every TV properly displays 1080p/24. The 24 refers to the true frame rate of film-based content, and displaying it in its native format is supposed to give you a picture exactly as the director intended you to see it (for a full explanation, click here).

Whether you're dealing with 1080p/24 or standard 1080p/60, doesn't alter our overall views about 1080p TVs. We still believe that when you're dealing with TVs 50 inches and smaller, the added resolution has only a very minor impact on picture quality. In our tests, we put 720p (or 768p) sets next to 1080p sets, then feed them both the same source material, whether it's 1080i or 1080p, from the highest-quality Blu-ray player. We typically watch both sets for a while, with eyes darting back and forth between the two, looking for differences in the most-detailed sections, such as hair, textures of fabric, and grassy plains. Bottom line: It's almost always very difficult to see any difference--especially from farther than 8 feet away on a 50-inch TV.

I said so much in a 2006 column I wrote called "The case against 1080p," but some readers knocked us for not looking at high-end TVs in our tests. But the fact is, resolution is resolution, and whether you're looking at a Sony or a Westinghouse, 1080p resolution--which relates to picture sharpness--is the same and is a separate issue from black levels and color accuracy.

Katzmaier stands by his previous analysis: The extra sharpness afforded by the 1080p televisions he's seen is noticeable only when watching 1080i or 1080p sources on a larger screens, say 55 inches and bigger, or with projectors that display a wall-size picture. Katzmaier also says that the main real-world advantage of 1080p is not the extra sharpness you'll be seeing, but instead, the smaller, more densely packed pixels. In other words, you can sit closer to a 1080p television and not notice any pixel structure, such as stair-stepping along diagonal lines, or the screen-door effect (where you can actually see the space between the pixels). This advantage applies regardless of the quality of the source.

10. OK, so what's the bottom line: Should I save some dough and opt for a 720p TV?

If you're just making the leap to HDTV and find the higher end sets out of your price range, you shouldn't feel bad about going with an entry-level 720p model (just getting HD programming is going to make a huge difference). Also, in a lot of cases, folks are looking at 720p TVs as second sets for bedrooms or playrooms, and in a tough economy, a few hundred bucks makes a big difference. Personally, if I were choosing between the 720p 50-inch Panasonic TC-P50X1 and the 1080p Panasonic TC-P50S1 for a bedroom, I'd strongly consider going with the cheaper model if it meant saving $600-$700. That savings is enough to buy another 32-inch LCD for another room.

If you're thinking of going big, really big (a 55-inch or larger screen), or you like to sit really close (closer than 1.5 times the diagonal measurement), the extra resolution may make it worth the difference--as long as you have a pristine, 1080i or 1080p HD source to feed into the set. (To be clear, there are few 720p sets available in large sizes anymore, though a few older models may be kicking around at good discounts).

Finally, it's a good idea to go with 1080p instead of 720p if you plan to use your TV a lot as a big computer monitor. That said, if you set your computer to output at 1,920x1,080, you may find that the icons and text on the screen are too small to view from far away (as a result, you may end up zooming the desktop or even changing to a lower resolution). But a 1080p set does give you some added flexibility (and sharpness) when it comes to computer connectivity.

If none of those factors jump out at you as true priorities--and you're working on a tight budget and want to save some dough--a 720p set is going to do you just fine. HD will still look great on your set, I swear.

11. Wait! What about 120Hz LCDs and how they compare to 720p/1080p plasmas?

This column's just about 720p vs.1080p. If you're interested in 120Hz, try reading "Six things you need to know about 120Hz LCD TVs."