Sadly, the entire topic of High Definition has become a minefield of myths and misinformation due to bad marketing campaigns and media speculation so we have taken it upon ourselves to product a definitive guide to the ins and outs of HDTV.

This HDTV guide will dispel all the confusion surrounding the High Definition TV phenomenon allowing you to become an expert on all things HD.

Now we know about the higher output resolutions of High Definition the benefits are easier explained and understood. As the amount of pixel information on the screen at any one time is going to be far higher (up to four times more) it follows that the images displayed are going to be clearer, more detailed and with richer and deeper colours. From the comparisons we have done to PAL, High Definition simply looks far more focused an image and when looking back at a PAL image it almost seems as if one has got the wrong glasses on! From this increased depth of field, far more detail suddenly comes into focus from the individual blades of grass on a football pitch to the texture of peoples skin. With this increased sense of realism images become far more lifelike, drawing the viewer deeper into the action as the images spring into life and allow emotions to be experienced first hand. Colours spring from the screen and give everything you watch a rich and vibrant intensity, adding an extra layer of clarity to ones sensory experience.

Before we get carried away with the marketing speak, it simply has to be stated that one only has to experience High Definition first hand to see and feel the differences and we can assure that it will seem dull watching anything else once the future has been witnessed.

Starting with the former, interlacing was developed in the late 1920s as a means of reducing the bandwidth required for video transmission without having to reduce resolution of refresh rate. The process involves single frames being split into odd and even lines, whereby the two split fields are transmitted and then scanned onto a screen at a quick enough rate to create a smooth sense of motion, effectively fooling the eye from noticing the split.There is, however, a disadvantage that arises from the interlacing process when watching fast moving images such as sport, which is that motion artifacts or jaggies become visible. These refer to the lines within the image appearing jagged or distorted due to ones eyes being able to see both the odd and even lines out of sync due to the movement on screen being too fast for the dual scanning process to keep up with. Progressive scanning, on the other hand, involves every complete frame of an image being displayed in a one pass scan rather than in two separate scans as with interlaced images. This relieves the problem of motion artifacts as jagged line can no longer appear as all the lines in the image are displayed at the same time.

Now going back to the different High Definition resolutions one can work out that that the best one is going to be 1080p as it involves an image made up of 1080 horizontal lines being scanned progressively. 1080p is what many are calling true or native High Definition, however, the bandwidth required to broadcast 1080p is too large to be viable for HDTV and there is so far very few screens that can display a 1080p signal. Blu Ray DVD players and HD-DVD players use 1080p as their full output resolution and there are players for both beginning to emerge onto the UK market but for now only such recorded media will allow for 1080p.

1080i and 720p are also classed as high definition, despite theoretically being of a lower standard than 1080p, and they are the current standard of High Definition broadcasting in this country. For example SKY HD involves broadcasts in both formats depending on which format the programs are filmed in. Both these formats, when done right, are clearly superior to the PAL 576 line format we have today and both can be classified as standard High Definition video images.