Beyond the Invisible - Help and Advice - Getting the Best Picture on Your Screen
Many of the screens you see in high street electrical stores show really poor pictures and many people wonder why they should pay so much money for a Plasma or LCD for such a poor image. The truth is many of these screens are simply poorly set up, but there are many factors that affect the quality of an image on a Plasma Screen or LCD TV or a Home Cinema projector.
Beyond the Invisible's service includes setting up your screen so that it delivers the best possible picture. To understand a little of how we do this you need to understand a little of how the TV picture is made up.
Back in the days when TVs were fat everything was fairly simple. In the UK we use a TV format called PAL which is made up of 625 lines of information. In fact only 576 of these lines actually appeared on the screen (the rest were used for teletext and the like) and worse than that only half of these lines were used at a time, first the odd lines and then the even ones. This is called interlacing and was used simply because the technology wasn't fast enough to show all the lines at the same time . If you got a picture you were happy with it, and if you used a VHS player you were only saving 300 or so of these lines which is why recordings looked fuzzy.
Technology has moved on a lot since then (just think of the computers they were using in the 70s and how much faster the one you are reading this on is). DVD marked the biggest change in the quality of images. It is capable of providing 480 lines of picture information, and it can provide all of them at once, not odd followed by even lines, this is called progressive and is shown as 480p. Many newer DVD players will upsample this to 720 progressive lines. So how do we get 720 lines of information onto a TV with 576 lines. To do this the image needs to be downscaled and this is done by the DVD player.
Then plasma screens started to come onto the market and things started to get a little more complicated. Initially plasma screens were designed for commercial use as large computer displays. They have a fixed resolution that it just like those of your LCD computer monitor. Many screens have a resolution of 800x600. So to get an image of 576 lines onto a display of 600 lines the image needs to be upscaled to fit. What sets apart good screens from bad screens is often this scaling technology. Two screens can use an identical display panel but can give very different results. Beware of screens from lesser known brands proclaiming their known brand panel. The panel may be good but the image you see is very dependent on the scaler in the display. LCD and Projectors offer even more varieties of resolutions and each includes its own scaler to deal with the 720p images from your DVD and the 576i images from say your Sky box.
The other part of the equation is how the picture signal is sent from one device to another. Again back in the days of fat TV everything was strung together using an 'aerial lead' - many different channels containing both picture and sound down one usually poor quality cable. Then when VHS players took hold the wonders of the Scart cable appeared. The next stage up was to separate the audio from the pictures and send just one video channel along the cable. This is known as Composite video. Then came S-Video as part of the S-VHS standard. Now S-VHS was a bit of a failure but S-Video was a useful spin-off. S-Video separates the colour of the picture from the brightness of the picture (the Chrominance from the Luminance) and sends these separately.
The next stage was to separate the colour part of the picture into its constituent parts. This is known as RGB or Component Video. RGB and Component are similar but different. Confusingly many DVD players and set-top boxes will output RGB on their scart leads but your plasma or lcd display may not have a scart socket only a component socket. In which case the RGB signal needs to be converted to Component. RGB or component are the best that analogue video can deliver.
For the very best picture from your display you should use an external scaler. The scalers in most display devices are either poor or a re biased towards one input or another. An external scaler can take any input source - Composite, S-Video, RGB or Component and scale it into the exact resolution required by your display device. This way the display device doesn't need to process the image at all before displaying it. The difference in quality is very noticeable, a good external scaler is in the order of £1000 and lets face it given the cut-throat price war in the flat screen market place no manufacturer is going to include a scaler of that quality in their product.
Beyond the Invisible can recommend a good scaler for you given your flat screen and source components. We will also set the scaler up using its many different variables to ensure a top quality image. Its like looking through newly cleaned and polished glasses - everything is in focus and more vibrant.
So that is the world of analogue video, but next on the scene is the realm of digital video and high definition television ->