HD Ready or not?
The HD Ready logo appears on all TV screens and projectors that are compatible with HDTV signals. HD Ready screens must meet the following specification:
Minimum 720 vertical lines (the latter figure when a resolution is written out, e.g. 1280 x 720)
Analogue component video and either DVI or HDMI inputs
Support for HDCP content protection
Able to display 720p (1280 x 720 at 50Hz and 60Hz progressive)
Able to display 1080i (1920 x 1080 at 50Hz and 60Hz interlaced)
The differences between 720p, 1080i and 1080p
Having decided to take the plunge and buy an HD Ready TV, you will quickly become aware of the many and often confusing HD formats.
HDTV broadcast pictures come in two versions. The first is 720p ("p" stands for progressive), which is an image comprised of 1280 lines along the horizontal by 720 vertical lines. It shows the whole image in a single frame – that is, progressively.
The second is 1080i, which measures 1920 x 1080 lines and is displayed as two fields that are interlaced. You get a bit more detail with 1080i but the interlaced image is not as smooth as a progressively scanned one.
A high-res screen with at least 720 lines will show both formats but only a 1080-line screen will show 1080i footage at its best, i.e. in an un-scaled form.
Note: You don't have to become too concerned with different HD formats. It is true that the likes of Sky, Virgin Media and the BBC are all different, even to the extent that some of their programmes use different formats; but, and this is the important point, an HD Ready TV will take any HD signal in any of the formats we have described and more, scaling it to fit the screen.
While 720p and 1080i are generally used to broadcast HD, you might also come across the 1080p format. Movies made in 1080p (the last three Star Wars films) are starting to appear on Blu-ray. Sony's PlayStation 3 produces 1080p output.
There are more and more 'Full HD' screens (capable of displaying 1080p) appearing. A 1080p screen can de-interlace a 1080i signal or upscale a standard definition one. With very few 1080p sources available, the main benefit of a Full HD screen is its ability to map a source such as Sky TV (1080i) pixel for pixel to the screens resolution (ie 1920 x 1080).
A word of caution
So you’ve decided to take the plunge, and dive into the exciting new world of HDTV. You’re anxious to get out there and buy your HDTV kit, but before you do, a word of caution ...
The stunning 50in Plasma and LCD TV's that greet you at the entrance of most major retailers are certainly impressive, but what they display is not necessarily available to you just at the moment. A little bit of ground work is required to find out exactly what is currently available, but don’t worry, here at HDTV org we’ve made it easy for you.
Remember that HDTV in the UK is in its infancy, and although programmes broadcast in HDTV are available, the current range of programme choice is a fraction of that available in the conventional format.
Your new HDTV will show all the programmes that you have been used to watching, but you will need to find out more about the providers who are currently broadcasting HDTV to determine exactly what you can watch in the new format, what equipment you will need, and how much its all going to cost.