Everyone needs High Definition, apparently. But what exactly is it? We look at what HD really means and what to consider when buying HD kit.
If you’ve read our Digital Cameras Demystified article, then you’re probably up to speed on how picture resolutions work – the more pixels the better because you see more detail in a higher resolution image.
High Definition, HD for short, is a blanket term that refers to image resolutions that are higher than, well, what we used to have. The idea then, is that if we’re getting something that’s HD, it’s going to give us a better picture than we’ve seen before. But HD means different things to different products, so how do we know what we’re getting, and if it’s really any better?
We’re going to focus on the world of television. It’s the area in which HD has the clearest definitions (because there are rules about what you can sell with an “HD” badge on it), and of course TV is where we hear HD mentioned most often, so let’s break down some of the buzzwords, terms and branding of HD television…
PAL
This is a method for displaying video that’s been in use for many years, used primarily in Europe. It’s used for analogue TV and in the digital world too, where it used to refer to videos that are 720 pixels wide and 576 high. It might be referred to in some places as “Standard Definition” or SD.
NTSC
This is the video standard that used across the pond in the USA. The resolution is slightly lower than PAL, coming in at 720×480 for digital broadcasts. Again, this can be referred to as SD.
PAL and NTSC are analogue standards, but the proliferation of digital TV saw the creation of digital equivalents to ensure compatibility and to make the transition simpler.
Progressive/Interlaced
No, HDTV isn’t heralding a new era of prog rock. Here, progressive means each image (frame) that makes up a video, contains a full complement of pixels. In an interlaced video, each frame switches between showing the odd rows and even rows of pixels, so each frame only sends half the number of pixels that get displayed. If the image is updated fast enough, we cannot notice an interlaced picture.
PAL and NTSC are both interlaced. Progressive images are generally better, especially with modern LCD displays, and in the HD world, progressive pictures can give a much smoother, clearer picture when there’s a lot of movement in the video.
Progressive and interlaced are often abbreviated to “p” and “i” respectively, when referring to video standards.
4:3
This is a ratio that describes the shape of a video. For every 4 pixels across, there are 3 going down.
16:9
AKA “widescreen”, videos are wider than their 4:3 counterparts. The vast majority of programmes are now filmed and broadcast in widescreen.
720
HD video standards are pretty easy to understand because the naming conventions give us most of the information we need. In this particular case, the image is made up of 720 rows of pixels. Combine that with the 1280 columns needed to create a 16:9 widescreen image (16 columns for every 9 rows) and we have 720×1280 – a resolution that’s more than double PAL and NTSC.
1080
With a resolution of 1920×1080, we get over four times more pixels than standard definition. Currently, this is the highest resolution HD video you can view via broadcasts, but over in the Far East they’re already using bigger and better standards.
1080 video can also be referred to as Full HD.
HD Ready
This useful moniker tells you that the television you’re looking at can receive high definition video signals. But that doesn’t mean it’ll directly receive HD broadcasts. It more likely means if you hook up a Sky HD box, BluRay player or similar, you’ll be able to get you a lovely HD picture.
HD Ready TVs must be able to receive up to 1080i images. However, they only need to display at 720, so depending on the TV set, 1080 images might get shrunk down, losing some detail.
For more information on the HD Ready logo, check out the HD Ready website.
HD Ready 1080p
To carry this badge, a TV must abide by a more stringent set of rules. It must receive and display image at up to 1080p. You’re still likely to need external receiver boxes to actually play HD content, although a growing number of TVs have some sort of HD receiver built in, such as freesat HD.
This handy diagram demonstrates the common video standards and the difference in resolutions.
HDMI
The High Definition Multimedia Interface is a type of connection capable of carrying HD video and audio. It’s the interface you’ll want to use to connect your HD gear together if you can. It’s digital, ensuring no noise or signal degradation.
Component/YPbPr
This is an analogue connection capable of carrying HD signals. It’s made up of three wires, labelled Y, Pb and Pr. If an HD capable device has no HDMI port, it’ll most likely have one of these instead, making it preferable over everything but HDMI.
OK, so I know what these things mean, but what do I want?
Now you can walk into a store and avoid being baffled by sales patter, but we still haven’t answered the big question: “What makes a good HD TV setup?”
Well, start with the TV of course – try to future-proof yourself as much as possible. Look for something carrying the HD Ready 1080p logo, unless it’s a smaller screen (26” or less), where you can probably get away with a 720 image, unless you’re sat really close.
A good HD TV will make SD broadcasts and things such as DVDs look a little bit better by up-scaling them to fit on the screen. But there’s only so much you can do without a full contingent of pixels, so to get the best picture you really need to feed your shiny new TV some HD content.
If you’ve read about the digital switch over then you’ll know that HD broadcasts are already here for satellite and cable TV, and are available in some places for over-the-air broadcasts too – even if none of us can actually see the latter yet. So the options are out there and growing.
For recorded content, there is of course BluRay, with lovely 1080 videos and impeccable sound. Be sure to avoid HD-DVD – the once competing standard that has since conceded defeat.
And if you’re a gamer then bask in the glory that HD brings to your console. Of course, Remember Kingston’s gaming fans already know this, having read our guide to great console gaming, right?
The road to HD bliss is fraught with confusion vocabulary, but hopefully today Remember Kingston has straightened out at least some of the facts for you. If you’ve got any questions, leave a comment and our boffins will duly respond!
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