Full HD or HD Ready?

A common term used in relation to television sets is ‘full high definition’. The switchover from analogue to digital television broadcasts in June 2009 has increased the exposure to the phrase Full HD TV. With digital television now being available to all in order to join the high definition revolution you are going to need to invest in a HD TV.

A point of reference worth knowing is that analogue televisions have a resolution of 640 x 480i, this is a handy fact to know in order help appreciate the comparisons of older standard definition TV with high definition TV. Why? Because the big difference and advancement that HD TVs have over their analogue predecessors is that the resolution (or the amount of pixels that make up the image displayed on screen) is far higher.

There are broadly speaking two common terms used when relating to the types of HD television available – HD ready and Full HD. HD ready includes 720i and 720p specifications and Full HD includes the 1080i and 1080p specifications.

As can be deduced from the numbering of these specs, both have a greater resolution with 720 and 1080 horizontal rows of pixels when compared to older analogue TVs meagre 480. The matter of which is the best or most suitable is not as straight forward as one might think. It is not necessarily a case of the higher the resolution the better for a couple of reasons.

Firstly the significance of ‘p’ and the ‘i’ used in specifications. The letters stand for progressive and interlaced scanning. To use an example if a television has a refresh rate of 100 Hz, this means that the image displayed on the television is refreshed or ‘recreated’ 100 times per second. If you can imagine the image is composed of horizontal rows of pixels or dots (720 or 1080 rows in the case of high definition TV). With progressive scanning every row of pixels is refreshed 100 times per second and with interlaced scanning only alternate rows of pixels are refreshed.

This has the result that 1080p produces a better quality of picture than 1080i (as does 720p when compared to 720i) and therefore 1080p is considered the best quality picture.

Taking this into consideration you should be aware of the following when choosing whether to buy a LCD HD Ready TV or go the whole hog and buy a big screen Full HD LCD TV. Firstly the benefits that come from progressive scanning are not particularly noticeable on smaller television sets and so progressive scanning is better suited to larger screen sizes. This is why smaller TVs tend to be manufactured to HD Ready standard.

Secondly not all high definition signals output by HD capable sources (eg TV broadcasts, games consoles, DVDs, BluRay, camcorders, PCs) are of 1080p specification. This means that you might end up using a 1080p capable television for displaying television broadcasts or a games console output of 720p. There is nothing wrong with this, but your television is not being used to its full potential and 1080p is not essential. It is worth noting that the vast majority of HD television broadcasts are in 720 i or p formats anyway.

So in summary if you are buying a small TV for your kid’s bedroom to watch TV or play old computer games, then a 20 inch HD Ready will most likely be perfectly suitable (and save you some money). However if you are buying a big screen for the BluRay home cinema setup then a 42 inch Full HDTV is probably the way to go!