AUDioImages

Basic, old fashioned CRT (Cathode ray tube) type TV's were 480i. The 480 means that there were 480 lines of "light" hitting the screen of your TV from behind (counting from bottom to top). Now let's call the very bottom-most line, line 1, the one above line 2 and so on, okay? 

The 'i' indictor means "interlaced". The problem with old analogue TV signals is that they can't carry very much data at one time (they have a small "bandwidth"), which makes it difficult to reliably get 480 lines of data to your TV at once. Instead, they actually only broadcast half of the signal, (lines 1, 3, 5, etc) and then right after that the other half (line 2, 4, 6 etc) in a separate transmission. If your TV keeps alternating the picture between odd and even lines fast enough, you don't see much of a difference. It is therefore “interlacing” the two separate pictures of 240 line each.

The other type of indicator you may have seen is 'p' (which stands for progressive), this means that the device is showing you all of the lines all of the time. That is to say instead of updating lines 1, 3, 5 and then 2, 4, 6, it updates 1, 2, 3, 4, 5, 6, all at once which makes for a much smoother looking picture, especially when your are watching something with a lot of fast movement like an action movie.

The screen resolution will also tell you the number of lines on the TV screen (for example if your screen was 1920 x 1080 this would be a resolution of 1080 lines top to bottom).

There are many "definitions" for TV types, but the most notable ones are, Standard Definition (SD), Enhanced Definition (ED) and High Definition (HD) and now UHD. SD simply means 480i (480 lines high, not all shown at once and 720 wide). ED means 480p (480 lines, all seen at once). So, anything that's left (anything with more than 480 lines) is considered HD. HD pictures are generally either 720 lines high or more likely 1080 lines high. Full HD is now accepted as 1920 x 1080. UHD (Ultra-High Definition or 4K) is 4096 x 2160. Finally, companies are already experimenting with mastering some pictures in a new Super Hi-Vision 8K format of 7680 x 4320 offering a staggering 33 million pixels on screen. It's certainly some way off yet, but it seems there may be no end in sight.

If you consider the number of pixels on the screen this highlights how higher definition pictures are made up of far more information than previous guises of pictures. See the following list which shows you how many pixels (lines) wide by pixels high and how many pixels the screen is therefore made up of:

SD: 720 x 480 = 345,600 pixels

Full HD: 1920 x 1080 = 2,073,600 pixels - or six times the information on screen of SD.

UHD 4K: 4096 x 2160 = 8,847,360 pixels - or four times the information on screen of Full HD or twenty five times SD.

SHV 8K: 7680 x 4320 = 33,177,600 pixels - or four times the information on screen of UHD or sixteen times Full HD and a crazy ninety six times SD!


From these astonishing figures we can see how things have changed over the years. Progressive is the best way to deliver a signal and 1080 lines is the highest number of lines in common broadcast use today (although 4K is very close). A 1080p TV therefore offers you the highest quality picture options depending on the signal it is supplied with. These are much more affordable now so unless you are looking for a real budget unit I wouldn't buy anything else. With the advent of UHD 4K, many TV's are being sold in this new format, although there is no current broadcast format to support it and no Disc version available to playback from. Many TV's that are in the 4K format upscale the existing 1080P signal to 4K, but as we've witnessed in the past, this is not always as good as it seems. Indeed, 4K TV's showing standard definition pictures from something like one of the ordinary non-HD format broadcasts or from a standard DVD look poor in comparison to even an SD set. The picture is fidgety and full of motion blur and does not offer a good viewing experience at all. However, full 1080P movies can look stunning.

For a long time LCD and Plasma HDTVs only came in 1080p (unless you had LOTS of money to burn), but more and more 4K sets are now out there, and at very reasonable prices and some of the curved screen options look very attractive indeed.

Now let's move onto how we get that HD picture to your TV. Just like music, your picture quality will only be as good as your weakest component. If you are listening to an old audio cassette, it doesn't make much difference how expensive your sound setup is, you are not going to get great quality music. The same is true of TV. 
People generally get their TV one of 4 ways, Cable, Streaming via the internet, Satellite or the Free over-the-air kind. 
All of these ways of receiving TV offer HD content (they broadcast a digital signal that can carry HD information). Most cable and sat providers can rent you an "HD Box" that will allow you access their HD content and Freeview/Freesat HD is now well established. Streaming services are available from a great many providers and can be accessed in any number of ways.

Those broadcasting HD may broadcast some shows in 720 lines, but most now come in 1080i. You should beware that in order to "save space" both cable and satellite providers compress their HD signals. Decompressing these signals for you to see is what their "HD Box" is doing (just like ZIP-ing a computer file). You will inevitably lose some picture quality due to this compression process but for most people the difference is minimal. 
You can watch a 1080 signal on a 480 digital set if you want but you will of course lose some of the detail. Likewise, you can watch a 480 broadcast on a 1080 set. In this case your TV actually has a small "brain" inside it, which creates new lines to make a full 1080 image (it looks at the line above and below the line it is creating and guesses what should go in the middle). This process is called "up-scaling". If you are going to be watching a lot of regular DVDs (which are in 480) then how well the TV up-converts should be a key question you want answered before you buy, although more and more people now are using Blu-Ray players with built in scalers to give your older DVDs a higher grade looking output. Just remember though, that a Blu-Ray player that outputs 1080 from standard Dvd is not making your DVD movie into HD - you can't make a silk purse out of a Sows ear as the saying goes. Further more, the quality of this 'scaling' varies tremendously.

Although 1080p sets can play up to 1080p signals, there are no broadcasts out there in any definition better than 1080i right now (and due to bandwidth restrictions, there won’t be for some time yet). However your 1080p ability comes into play with the new High Definition Blu-Ray formats and on streamable content from people like Amazon and Netfliks. These both send out a 1080p signal, for the best picture quality possible. However, they do compress the signals, so a Blu-Ray version of a 1080P movie will still look much better than a streamed version even though it is in the same 1080P. Confused?

In short, when you are out and about, try to look at any 1080p or 4K TV. If you are looking at it in a shop try to see if they can show you a standard 480 signal on it as well as HD to see how it handles both types of signal. LED screens in particular are very poor at showing lower resolution pictures. Ironically good old fashion CRT TV's do a better job of that than anything new! Newer OLED TV's can look particularly good with black levels exceeding even Plasma TV's.

We hope this helps!

If you have any questions feel free to contact us.