High Definition (HD) Info

Guides

Summary

The Audio and Video market has never been more confused and High Definition (HD) is the reason.

At the moment you’re probably like the vast majority of us: you have a DVD player and you keep hearing terms like HD-Ready, Full-HD, Blu-Ray, HD-DVD and "Hi-Def" Televisions and you’re not sure what it means and how it relates to you. Hopefully we can help you a little and then you can decide whether High Definition even matters to you

Which Should I Buy?

It’s hard to say as there’s no “one size fits all”.

We’d say if you’re happy with a TV less than 32" then there’s little point upgrading and you can stick with DVD and standard TV content and be very happy.

However, if you want to buy a new TV bigger than 32" (and you’ve already made a decision between Plasma and LCD technologies) then the points below should help

• If you’re going to play a lot of Xbox 360 or PlayStation 3 games then HD-Ready is enough (see HD-Ready guidance below)
• If you want the best quality display for new movies then select a Full-HD set and buy a Blu-Ray player and disks to compliment it
• If you’ll be watching a lot of standard TV and DVDs (but you want a TV over 32" in size) then HD-Ready will generally look better (but make sure you follow the guidance below on which TV - cheap sets typically are cheap for a reason)
• If the TV you’re buying is greater than 50" then you’ll be needing Full-HD support so the picture doesn’t start looking blocky even with High Def content (either satellite/cable HD channels or Blu-Ray).

But for most of us you’ll want to know all the pros and cons - so read on (and let us know your comments!)

What Does HD Mean

For years DVD has been the king of viewing (and soundtracks) and has given us an excellent picture with great sound. However DVD was created for TV screens no larger than 32" and now that TVs are getting bigger (largely thanks to Plasma and LCD Televisions) DVD is starting to look old.

The reason is simple: DVD encodes a picture as a set of dots/pixels (just like your printer prints out pictures and text) arranged in to a number of lines. For years this was good enough because although TVs were getting larger the dots/pixels were still small enough to show detail in the picture, and because non-LCD/Plasma (i.e. CRT) TVs smoothed out any problems.

DVD (like TV transmissions) has either 480 lines (or more typically in the UK and EU) 576 lines of detail.

LCD and Plasma TVs are extremely precise when they show pictures so the picture starts to look like it’s made out of dots/pixels and thus the picture doesn’t look great - so High Definition formats were invented

High Definitions Formats (HD-Ready and Full-HD) try to address problems in TVs by adding more dots/pixels and lines to the picture. In that way because there are more dots/pixels even at large screen sizes the picture looks good (as the individual dots/pixels are still small).

However, there’s a catch; and it’s a large one...

The Catch with High Definition Televisions

Manufacturers have increased the number of dots/pixels on the screens so things should look better right? Well sorry, there’s a catch: and it’s a big one.

When you feed a DVD or your Television picture (eitther Analogue or Digital signals from Freeview or the standard (non-HD) Sky or Cable packages) the signal still only has the original amount of dots/pixels as before. So now your TV displays twice (or so) the number of dots/pixels that it used to but it’s only getting information about the colour and brightness that 1/4 of them should be... so what does it do? It guesses the rest!

This is called "upscaling" and means that your TV is guessing what colours and brightness the other dots/pixels should be, and because it’s a guess (although a complex computer algorithm makes the guessing pretty good) it can never look as good as if it got the full signal containing all the dots/pixels.

What you need to understand with HD televisions is that this upscaling is very very important to your viewing. At the moment most TV channels are not transmitted in High Def (see our guide on Freeview with High Definition TVs for more information) so this upscaling is always going to occur. Also I doubt any of us are going to throw away our DVD collections so we’re going to be using non-HD sources with HD Televisions for quite a while.

There is good news though: Sony’s Blu-Ray format appears to be the next generation High Definition format to succeed DVD, and a limited TV service is now available from various providers for those using Cable or Sky services

HD-Ready (aka 720p support)

HD-Ready is the MINIMUM that a TV needs to be High Definition, however that’s not always a bad thing (don’t assume that Full-HD is better than HD-Ready in all ways - see the guide to Full-HD for more info)

HD-Ready means that you can support a standard called "720p" - all that means is that TVs that are marked HD-Ready (but not Full-HD) have 50% more lines than a standard television, and that effectively means it’s got double the number of dots/pixels than a standard television.

Most PlayStation 3 and Xbox 360 games handle 720p so it’s a good format for games players and unless you need an enormous TV it’ll look great.

Lastly, although Blu-Ray and HD-DVD disks output at Full-HD (aka 1080p) HD-Ready TVs will cut down the picture to size, yes you lose some detail but because it’s throwing away information (rather than guessing what detail should be there like upscaling needs to do) the picture will still look great.

Full-HD (aka 1080p support)

Full-HD is supposed to be the holy grail for large TVs and is the format that both Blu-Ray and HD-DVD disks output at 1080p (that’s 1080 lines of detail vs. HD-Ready’s 720 lines of detail) and this means that a Full-HD TV has roughly 4 times the number of dots/pixels as a standard TV. So for Blu-Ray and HD-DVD you’ll be getting the best available picture.

However, this isn’t always great. Some High Definition TV providers only provide video at 720p (HD-Ready) levels - so you’ll still be upscaling content to your screen, plus the PlayStation 3 and Xbox 360 typically use 720p as their game video output - so again you’ll be upscaling to play games.

1080i - The compromise format

Just to confuse the market further HD-Ready TVs support a format called 1080i (note the "i" instead of the "p" that’s used against Full-HD). This doesn’t mean they have 1080 lines of detail like Full-HD content, instead it just means that the TV will support the signal and downscale it to fit.

1080i is really a way of transmitting data so that a frame of video is split into two passes instead of one (it’s a bit techy - see wikipedia for more information on 1080i if you’re interested).

Some High Definition channels will use this format to transmit their TV content - the truth is that it’ll look better on Full-HD sets than it will on HD-Read TVs.

UpScaling

We’ve already mentioned that upscaling is important, so you’re probably thinking "how do I know which TVs are good at upscaling and which aren’t". Well there are a few general rules that apply;

1. Price is a reasonable indicator (Sony Bravia TVs for example beat cheaper Far East LCD/Plasmas for the same size)
2. The "Chipset" used is sometimes an indicator - we love the TVs using Faroudja’s DCDi Edge technology and look out for new models using even better chipsets like HQV’s Reon-VX.
3. Go and look at the TV with a standard TV feed in it - if it looks better to you then that’s good enough

Lastly, if you’re looking at a Home Cinema package then ensure that you’re AV Receiver handles upscaling - if you’re buying a quality Receiver then there’s a fair chance it’s upscaling capabilities are better than your TVs

Freeview (in the UK) and High Definition

Freeview won’t be going High Definition any time soon, so you’re stuck with standard definition and upscaling.

In future Freeview will add High Def content, but to get it you’ll have to buy a new Freeview box. In any case there’s no date for it, and most channels will stay in HD, so you can safely ignore it for the moment.

If you do want some Freeview channels in HD then you could use FreeSat which is launched in early 2008. For this a single purchase of the box and satellite dish will allow you some BBC and other channel’s content in 1080i HD - so for Full-HD viewers it’s going to look very good (although in fairness it’ll downscale for HD-Ready users so it’ll still look "twice as good" as standard TV for those users)