The number of pixels on a television panel, or its
native resolution, determines the amount of detail you'll see on
screen. So, it's worth paying more for higher resolutions... or
is it?
You're in your local consumer electronics store looking at 42-inch plasma TVs side-by-side, and they're playing the same high-definition demonstration footage that stores typically use to make TVs look good. Cosmetically, the sets appear very similar -- until you examine the little price/information placards. One set costs AU$2,999, one AU$4,999, one AU$6,499 and still another other costs AU$6,999. The pixel resolution on the cheapest set is 852x480, two others are 1024x768 and the other (not the most expensive set) sports 1024x1024 pixel resolution.
When you look a bit closer, you may think that one plasma looks sharper than another, but which set should you buy?
The fix is in
Welcome to the confusing world of fixed-pixel displays. All
fixed-pixel TVs -- including every flat-panel LCD and plasma as
well as rear-projection televisions that use DLP and LCD
technology -- have a certain number of pixels, known as the
native resolution, that they use to create the
picture. With these types of displays, the native resolution is
the absolute limit on the amount of detail you'll see.
In Australia, you may hear of standard definition (SD) broadcasts, which have a resolution of 576i (576 horizontal lines -- interlaced). To qualify as a high definition (HD) broadcast, the minimum picture resolution must be at least 576p (576 lines x 720 pixels per line -- progressive). HD can also be 720p (720 lines x 1280 pixels -- progressive) or 1080i (1080 lines x 1920 pixels -- interlaced). For more on the flavours of digital television see our feature on Digital TV in Australia.
Regardless, fixed-pixel displays follow a few basic rules:
- No matter the resolution of the source material, whether VHS, DVD, or HDTV, a fixed-pixel display will always convert, or scale, it to fit its native resolution.
- If the incoming source has more pixels than the display's native resolution, you will lose some visible detail and sharpness, though often what you're left with still looks pretty good.
- If the incoming source has fewer pixels than the native resolution, you're not getting any benefit from the extra resolution. In almost every case, extra pixels will not make a lower-resolution source look better. All other things being equal, the same DVD shown on an HD and a non-HD plasma will have the same amount of detail.
Here are some examples of how native
resolutions interact with DVD and HD sources in the real
world:
32-inch (81cm) analog TV
|
42-inch (106cm) plasma
|
42-inch (106cm) HD
plasma
|
50-inch (127cm) or larger plasma;
23-inch (58cm) or larger LCD; 720p DLP or LCD
rear projection
|
1080p flat-panel LCD; 1080p DLP
rear projection
|
|
| What is the native resolution? | No exact number, since it doesn't use pixels, but the amount of detail, for a good analog TV, would be the equivalent of 640 x 480 pixels. | 852 x 480 pixels | 1,024 x 768 or 1,024 x 1,024 pixels | 1,280 x 720, 1,280 x 768, or 1,366 x 768 pixels | 1,920 x 1,080 pixels |
| If you feed it an HD signal, will you see a picture? | No | Yes | Yes | Yes | Yes |
| Will it display every pixel of wide-screen DVD? | No | Yes | Yes | Yes | Yes |
| Will it
display every pixel of 576p? (ABC, SBS, Seven) |
No | No | Yes | Yes | Yes |
| Will it display every pixel of 720p? | No | No | No | Yes | Yes |
| Will it
display every pixel of 1080i? (Nine, Ten) |
No | No | No | No | Yes |
1080p
There's another native resolution that's available in flat-panel
LCDs and rear-projection televisions: 1080p. These sets have
imaging elements with 1,920x1,080 pixels, which should allow them
to display every single detail of 1080i high-def TV sources. We
say should for a reason: the real onscreen
resolution still might be less than all 2 million pixels, for a
variety of reasons. With flat-panel LCDs, video processing can
soften the visible resolution. With rear-projection sets, the
brightness-enhancing screen can also soften resolution,
especially in models smaller than 60 inches diagonal. Whether or
not these sets can handle every pixel, however, they provide the
benefit of smaller, more closely packed pixels, meaning you can
sit closer and not notice the pixel grid -- the screen-door effect. And they definitely provide sharper
pictures than 720p native-resolution sets, regardless of whether
they actually resolve every detail of 1080i.
How much does pixel count matter?
If we go back to the example of the otherwise similar plasmas
above, the question remains: Is it worth another AU$2,000-$4000
to get the more pixels, or is 852 x 480 enough? Keep in
mind the following:
- DVD and standard TV will look basically the same on both.
- Non-HD plasmas generally have better black-level performance and higher contrast ratios than their HD siblings, which lead to better-looking dark scenes.
- HD plasmas will look significantly more detailed with HD and computer sources, even though they don't show every pixel.
- HD plasmas have smaller pixels, allowing you to sit closer without discerning the pixel grid.
Ultimately, the choice comes down to whether you believe the increased resolution with high-def or computer sources is worth the price difference and, in some cases, the trade-off in black-level performance. Keep in mind that TVs last a long time and that more and more HD programs and sources (such as Blu-ray and HD-DVD) are becoming available, so you'll have more opportunities to take advantage of extra pixels in the future.
Resolution isn't everything
Before you rush out and buy a plasma purely on the basis of its
pixel count, remember that resolution is only part of the story.
Performance among fixed-pixel displays still varies widely, and
colour accuracy, black levels, video processing and the rest are
all important factors in picture quality. What's really the best
way to know
which fixed-pixel TV to buy? Decide what kind of input you
will spend the most time watching, research your purchase using
CNET.com.au's TV
reviews, and ultimately, go into a store and see for
yourself.
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john58
25/09/2005 05:27 AM
True the less resolution the worst the video is just like 852 x 480 pixels, analog compare to HD. The article also said "You're in your local consumer electronics store looking at 42-inch plasma TVs side-by-side, and they're playing the same high-definition" which is not true they are not showing HD but a recording like a loop of some sort, which looks awful. 720p is hardly HD. To make sure your getting true HDTV make sure it has 1080p, 1080i, 720p all in one TV like Samsungs HLR6168w other wise person would feel cheated if the video doesn't look 3d
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Nick
25/09/2005 03:34 PM
I bought an LCD TV with the 1366 x 768 pixels, not because of these numbers, but because it had the best picture for the price I was willing to pay. I never even thought about comparing the SD vs HD resolutions, however I'm glad I got the resolution I did because I use it as my computer monitor - 1366 x 768 is a low resolution in computer terms, so those of you who are buying a monitor replacement make sure you get as high as possible! And just to the other feller who posted, 1) 720p is probably 'more' HD than 1080i: there are more lines displayed at any one time with 720p (720 in one pass) versus the 540 per pass for 1080i (1080/2, as it displays the odds, then the evens). Having said this, I cannot tell the difference between the two, and much research into it has told me that there is practically no visible difference. However this is just my observations, and may be wrong!!!!
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dudez
21/02/2006 05:13 PM
You've said that the 852x480 plasma will display every pixel from a widescreen DVD source, but this isn't the case as DVD's encoded in PAL are in 576i.
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Maximus XCV
19/08/2006 11:35 PM
PAL Progressive Scan, is in fact 576P that is 576 lines displayed in every pass, so how exactly does an 852 x 480 plasma show 96 more lines of pixels than it has? This is the one advantage PAL has over NTSC, 50hz (PAL) might be a slower refresh rate then 60hz (NTSC), but 576P for a Prog Scan DVD is a better resolution than an NTSC DVD @ 480P. I agree with many points in the article and will probably get the standard resolution for a HD-LCD - 1366x768. BTW I still run my PC at 1024x768, even for Oblivion and FEAR Combat and I don't really think that there is much point raising the resolution much further - after all Half-Life 2 at 16:9 has a maximum resolution of 1366x768.
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Tim
07/11/2006 03:41 PM
For a computer monitor (especially for gaming) a higher resolution makes a lot of difference, the whole picture becomes a lot sharper and more detailed and you don't have to use AA to get ride of those jagged lines. When your using it for tv/home theater, the difference isn't as big as you ussually sit a lot further back.
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