Wednesday, December 29, 2010

Aspect Ratios and other Tips

After all the hard work of choosing your HDTV, the TV is delivered and now is the time to switch on the new toy, sit back, relax and enjoy the fruit of your labour. But what, why is the picture not looking as good as in the showroom? Why are there black bars on both sides of the screen? Why do all the people look fat and distorted on my new screen?

Here are some answers. Your HDTV will only look good and proper when displaying HD source materials at the correct aspect ratio. If you are watching your old VCD, DVD or SD (standard definition) TV broadcast, your HDTV will not magically make them look like HD. You need to have HD source materials to display or you will be disappointed. In fact some SD material will look worse since the higher resolution of the HDTV actually magnifies the old SD material and the imperfection will be more apparent.

All the material they play on the HDTV in the showrooms are specially prepared demonstration material or selected Blu-ray Disc (BD) movies to bring out the best in the HDTV visually. (The current favourite demo movie seems to be Avatar.) So your run of the mill HD material may not be as good as the demo items but definitely better than normal SD material. Your best source of HD material is undoubtedly BD movies, both visually and also audio-wise. Alternatively, downloaded HD movies and TV series (legally or otherwise) are getting popular and these can be played on your HDTV with a HD Media Player.

Another good source will be HDTV either delivered on cable or via satellite service (like the local Astro Byond). In the more advanced countries, they will have VOD (video on demand) or HD movie rental via the internet. To enjoy your HDTV to its full potential, you must get one or some of these HD programme as the source. Just note that not all HD movies or programmes are created equal, you will find some looking better than others so do not expect all of them to be of demonstration quality.

What about the black bars on the sides and the distorted picture that fill your screen? This bring us to the aspect ratios of TV screen. The older CRT TV and PC monitors have squarish screen size that is referred to as 4:3, i.e 4 units wide and 3 units high or an aspect ratio of 1.33:1 (which is 4 divided by 3) and this is called standard screen. When HD program came along, a standard screen size for HDTV is 16:9 i.e. 16 units wide and 9 units high or 1.78:1 (16 divided by 9 = 1.777 and is rounded off to 1.78) and this is known as wide-screen. Even PC monitors nowadays are wide-screen at 16:9 and 4:3 monitors are a rarity.

Those anomalies we see is because of these 2 different aspect ratios and we will limit ourselves to what we see on the HDTV. If you watch standard SD material (those with 4:3 settings) you will see black bars on either side of the HDTV since is is wide-screen and hence too wide for SD material. For some people, having paid so much for a new HDTV, they would want to fill up the whole screen to fully utilise their investment. There are at least 3 ways to do it and most HDTV will have these options or more. The first one is Full (or call Stretch in some brands) so the SD material will be stretched sideways and people will look fat and squashed. This is the one used by most people. The second one is to use the Zoom function to fill the screen with the picture. In this case, the SD material is made bigger all round, keeping the right proportion but then the top and bottom part of the picture will be missing. The third option is less common where the stretching is done at the corners to fill the screen and the result is that distortion is more at the corners while the centre is near the correct proportion. This is called Super Live, Panorama, Theatre Wide or some other term as used by different manufacturers.

Actually getting a HDTV is to get the best picture so using any of the above 3 methods to get rid of the black bars at the side is really sinful since it will result in distorted picture or missing parts of the action. One should live with the black bars but then it is up to the individual so as a result we see a lot of fat and squashed people on HDTV screens.

Just a word of caution for new Plasma TV owners. Though there is great improvement in this area, there is a possibility of image burnt-in for Plasma TV, especially during the early or run-in period; each model has different run-in period so check your user manual. During this period, avoid prolonged period of black bars on either side, i.e. view your material in full screen even if it is distorted. After this you can choose whatever settings you like. LCD TV do not have this image burnt-in problem.

How come sometimes I can see black bars at the top and bottom even though I am playing a Blu-ray disc, shouldn't the picture fill the whole screen? Well there is nothing wrong with your TV it is just that not all movies are shot at 16:9 (or 1.78:1) as some are extra wide at 1.85:1 (which is the standard 35mm movie ratio) and even 2.39:1 (CinemaScope or panavision ratio) so if these are shown on the HDTV screen, there will be black bars on the top and bottom as these movies are wider than the HDTV screen. To get rid of these bars, you can zoom your TV but you loose out parts that are on the sides. Again, it is best to watch with the black bars as you will be watching the movie in the format the director intended.

If you are having a HDTV for the first time, the first thing you must do is to set your DVD or Blu-Ray disc player to display on wide-screen TV or 16:9 Normal so that your movies will be shown in the correct aspect ratio without distortion or losing part of the picture.

On some HDTV, there is a selection for Store or Home so you should set it to Home for normal home use. In the Store mode, the brightness and contrast is preset to the maximum to attract attention. That is another reason why the TV looks good in the shop as it needs to compete with all the other models. But this shortens the life of the TV screen so the Brightness and Contrast should be turned down for home use. More on calibration in another post later.

To get the best picture quality on your HDTV, always use a HDMI cable for all your connections to the picture source. And you do not need to get a monstrously expensive HDMI cable, just one from the hypermarket or corner PC store will do. As the signal is digital (just ones and zeroes), either the signal is there or is not and thus either the cable works or it does not. Nothing in the cable will make the picture look better, even if it cost a bomb.

Ronald Kwok

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