High Definition Televisions
High Definition TV, or HDTV as it is commonly known, is simply a widescreen (an aspect ratio of 16:9), digital television with a resolution of more than 720i and connectors that allow a connection to a HD source. As nearly all televisions sold for many years have been widescreen and most have been capable of receiving a digital signal our attention is on high-definition TVs and more specifically Full HD TVs.
Before going into Full HDTV we thought it might be useful to start with the basics of HDTV, so here goes:
What is HDTV?
In simple terms a high-definition television (HDTV) produces a clearer, more detailed picture than a standard-definition television (SDTV). It’s all about resolution which is simply the amount of lines of pixels displayed. In high resolution the pixels are smaller and closer together HDTV has either 720 or 1080 lines of pixels whereas SDTV have significantly less (720 x 576 pixels in the UK). The resolution of your TV will be the amount of vertical lines of pixels x the amount of pixels within those lines. Therefore a Full HDTV with a resolution of 1920 x 1080 will have over 2 million pixels which is five times more than a standard TV. Hi-Def can be displayed on an old-style CRT screen but it is usually displayed on a flat-panel LCD or a plasma screen.
High Definition is broadcast in widescreen (a screen ration of 16:9) with a digital signal. Most TVs are now widescreen and are either 1280x720 or 1920×1080.
An HD TV also needs appropriate connectors for your video source i.e. Sky HD Box, Freesat, Blu-ray player, Sony Playstation 3.
Why upgrade to High Definition TV
It’s all about picture and sound quality. Most programmes and films are now shot in high definition and unless you have a television capable of showing them you’re missing clear, crisp images and amazing sound.
- VIDEO Sharp and clear picture quality - up to 5 times more detail than SDTV
- AUDIO Cinema-style 'surround sound' from most movies and some programmes
- MEDIA Broadcasts from Freesat (BBC & ITV), Sky HD, Virgin Media, HD DVD & Blu-ray
Why Choose a Full HD over an HD Ready TV
The main reason for choosing Full or ‘true’ HD is to display 1080p content delivered through a source such as a Blu-ray player, HD DVD player or games console capable of 1080p output.
Although an HD Ready TV can accept HD signals they may not accept 1080p signals and will down-scale the resolution. So, for an ultimate HD experience you need a 1080p HD TV where you can enjoy watching Blu-ray discs and HD DVDs which deliver full 1080p picture quality.
If the best movie-watching experience is high on your wish list and you have already purchased, or are intending to buy, a Blu-ray player please also see the paragraph relating to 24p in the ‘Choosing your Full HDTV’ section below.
Choosing your Full HDTV
So, in order to experience the full benefits of High Definition broadcasts you need to choose a television with a resolution of 1920x1080 but you also need to look for the ‘p’ appended to the resolution e.g. 1080p. The ‘p’ is for progressive and relates to the scan, or how the lines of pixels are built and displayed. A Full HD TV (1080p) has 1080 lines of pixels displayed progressively where each ‘scan’ displays every line in the image with one scan of the signal. HD TVs showing 1080i scans signals twice and displays alternate lines ‘interlaced’ in the image raster. A progressive scan will obviously produce a more stable image. Although at the moment most TV broadcast systems (including Sky HD) send signals with a maximum of 1080i (interlaced signal) choose a 1080p (progressive scan) TV if you can in order to benefit from Blu-ray disc technology and HD DVDs where the picture matches the resolution of a 1080p screen without loss of resolution.
Another point that you may wish to consider is the frames per second (fps) that the TV screen displays. Most TVs display video at a rate of 60Hz (60fps). With cinema quality movies filmed at 24fps and the next-generation HD sources (Blu-ray Palyers, HD DVD players etc.) outputting at 24fps a Full HDTV 1080p capable of displaying 24fps (1080/24p) are the ideal screen for optimum viewing of movies just as they were intended to be seen. If you have a HD player that outputs at 24fps and you view the media on a screen that only displays 60fps (60Hz) then you are likely to see what is termed ‘motion artifact’ or ‘Judder’.
