Secrets Q & A
- Written by Brian Florian and Colin Miller
- Published on 30 November 2007
- High Definition 1080p TV: Why You Should Be Concerned
- Page 2: Flat Panel HDTVs and the Caveat No One Wants to Talk About
- Page 3: Native 1080p Material - A Hidden Reality
- Page 4: But, Do You You Really Need 1080p?
- Part 5: Are 1080p Scaling Artifacts Worth Worrying About?
- Part 6: Conclusions About 1080p
- All Pages
But Do You Really Need 1080p?
Well, the first thing to come to terms with is, that, as we've pointed out, there is an abundance of 1080p24 material out there, encoded into 1080i60 format. If you want to view it at its full potential, you need not only a device capable of displaying it, a so called 1080line TV, but the ability to actually de-interlace it properly.
Some will argue that if you are seated far away and/or the screen is not enormous, one won't "appreciate" the full detail of 1920 x 1080 (as compared to lower resolution TVs). Well, if you look at a 27" 480i TV from 20 feet away, you could make the same argument. We could also make the argument that most people don't appreciate, or even know of, reasonably good video quality to begin with. The strongest argument for that is to look at the quantity vs. quality of channels available from your satellite or cable provider in standard definition digital format vs. a good DVD in the same format, or even a standard definition terrestrial broadcast with a reasonably good signal. Even the most massive compression artifacts are apparently acceptable enough to most viewers such that most broadcast content providers fill up bandwidth with hundreds of programs (and maximize compression to do it) with little complaint from their subscribers.
In that realm, if that's your baseline, then yes, the 1080p vs. 1366 x 768, or whatever your number, is more of a feel good numbers game. But, that's not us, and if you're reading this, we're betting that's not you either.
The point is, if you want to view the inherently 1080p24 content which is out there (and even native 1080i content) with maximum resolution (and we maintain that an enthusiast who sets up their viewing environment to get the most out of it can see the difference), you need a display capable of 1080p that keeps the signal in a 1080 line format from input to display surface.
Now, if we want to get into the evils of scaling, we could say that anything other than 720 x 480 displays are a compromise when watching standard definition DVD content, which is indeed true. However, this requires some kind of practical sacrifice.
To illustrate this, we are going to use simple vertical line patterns. We've zoomed them up to make them easily viewable on your computer screen. They are of course only 1/10th the full raster, but they make the same point (if you imagine each pattern stacked 10 x 10 to fill a display, you'll get the whole picture).
Our 'original' image is black lines, one pixel wide, with white space two pixels wide, between them. We're going to scale that up first. We will actually do it two ways. First, we'll do it the cheap way, where the scalar simply replicates data to fill in the spaces. Secondly, we'll do it the better way, which involves filtering and interpolating data so that each new pixel value is a best approximate guessed value of what it would be if it were re-sampled from the original image (but it can't be.)
In the below picture, the cheap way that simply replicates existing data to fill in the 'extra pixels' the smallest set of vertical lines is the original 720 x 480, then we show what happens to that when scaled to 1366 x 768 (next largest) and then scaled to 1920 x 1080 (largest) respectively.
The artifacts are not immediately apparent, but notice that in the 1366 x 768 scaled from the 720 x 480 pattern, all of the vertical lines are not the same width, nor is the spacing of white versus black the original 2:1 ratio. Similarly, on the 1920 x 1080 pattern scaled from the 720 x 480 pattern, while the width of the black lines happens to be constant, the 2:1 ratio of white space to black line is not.
Click on the photo below to see a larger, animated version. You may see a small square in the bottom right hand corner. If so, you need to click on that square to see the photo at full size.