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

Thursday, December 23, 2010

HDMI and other Inputs

If you have followed my previous posts, you would have narrowed down your choice of a HDTV. There are other features that you may want to consider before making the final decision.


HDMI inputs
The more the merrier. Make sure there are enough HDMI inputs to connect all your intended equipment with HDMI outputs. Normally you will need at least 3 (depending on your set-up) - one for you cable/satellite TV box (like Astro), another for your DVD/BD player and the third one for your gaming, camcorder, HD Media Player and other gears. If you have the newer AVR, then this number is not so important since you can connect most of your gears to the AVR HDMI inputs and with just one HDMI cable out to the HDTV. If your chosen HDTV do not have the number of HDMI inputs required, you just have to pull the cables in and out when necessary or maybe you can get one of those multi-HDMI (many in, one out) adaptor.

RCA connectors
To connect your DVD player or other gears without HDMI output, you will need either the composite terminals (red, white, yellow) or component terminals (red, blue, green). Most HDTV will have both these inputs, otherwise choose the one with the component inputs since this will give a better picture on the HDTV. S-video input is now less common.

RGB/PC terminal
You will need this if you intend to connect up your PC or laptop. Most if not all LCD TV has this, but for Plasma need to double check. You should go for a Full HD model if you want to hook up a PC or the lower resolution will show up.

USB and Memory Card slot
Some models have a USB slot to connect a thumb drive or external HDD to play music, photos and videos but the video files format support differs from model to model. Some have a Memory Card slot (like Sony and Panasonic to support their cameras and camcorders directly) for you to view photos and videos. Personally, I feel it is better to get one of those HD Media Player which is more versatile and has more functionalities then the ones built-in with the HDTV.

Other features

Screen style
Plasma screen usually reflects more light while LCD are normally matte but newer models are more glossy so you need to pick the one that best suits your viewing environment. Too much reflection will spoilt your viewing enjoyment.

Viewing angle
LCD can never beat Plasma in this area. All LCD TV will have a smaller viewing angle than Plasma but this differs depending on the make. Look from the sides of the LCD TV to see how bad the image is affected but in practice it is not critical since most of us will be watching from the front and not too much from the sides of the TV.

Cinema Mode, 24p
This is also called Real Cinema, Real Movie, etc. by some brands. Movies are shot at 24 frames per second (24p) while the normal rate for videos are 30 frame per second (30p) in NTSC or 25 frames per second (25p) in PAL. So to get the right movie feel, some HDTV have this 24p cinema mode. Note that this will only work if the source is also output at 24p and Blu-ray Disc players can do this. Like in many other features, some models of HDTV can do it better than others. To most people, the improvement is slight and many people cannot see the difference unless the two rates are displayed side by side. So this is more for the purists and videophiles.

Generally, the bigger the set, the better the sound and the higher end models will sound better than those at entry level. But really, to complement the HD video, you should hook up an AVR to enjoy the HD sound, especially from Blu-ray discs for a complete enjoyment of HD.

Picture Adjustment
Calibration enthusiast may want to check what parameters are available for tweaking. All HDTV will have enough video/colour adjustments provided than most of us can handle.

Intra-brand Connectivity

If your already have equipment from a particular brand, you may want to consider the advantage of getting the HDTV of the same brand (if the critical specs meet your requirement) such as using one remote control for all the equipment.

WiFi and Internet connectivity
Some higher-end models may have these functions. Only you can decide if you really need these, at a cost.

Finally, there is the physical built and how the HDTV looks and blends in with the rest of the furniture. For that, we better leave it to the wife or mistress, oops, I mean the missus.

Ronald Kwok

Wednesday, December 22, 2010

Contrast Ratio, Response Time, Refresh Rate

There are some specifications for LCD TV which potential buyers may want to compare but find confusing. The two common ones are Contrast Ratio and Response Time or more commonly used now, the Refresh Rate. For Plasma TV, these are not issues since inherently Plasma TV are better than LCD TV in these two areas. The first one, Contrast Ratio, should be totally ignored as this is the one spec that is really useless and often misused by some manufacturers.

By definition, contrast ratio is the ratio between the brightest white and the darkest black a TV can display and you see figures ranging from 30,000:1 to the ridiculous 5,000,000:1 or even higher quoted by some manufacturers. Does it mean that the later is 500 times better than the earlier one? Definitely not.

Here are the reasons why you should not look at this Contrast Ratio at all. Firstly, manufacturers do not tell you how they come up with the figures as there is no standard agreement among manufactures on how this should be done so it is free for all in this area and some manufacturers keep on increasing this figures hoping to boost sales in the process. So it is pointless to compare figures between manufacturers. These figures are probably measured in a totally dark laboratory and once there is some ambient light where we put the HDTV, these figures go out the window. Secondly, our eyes can only differentiate contrast ratio of up to about 1,000:1 normally so anything above that, the difference is not noticeable unless you are a robot. These fantastic figures are measured for static images so it has no meaning when we watch movies on the TV.

Among manufacturers, LG seems to be quoting higher and higher contrast ratio figures while Toshiba is using a comparatively modest 50,000:1 for all their LCD TV. Samsung used to be like LG but now it does not quote figures but just uses terms like "high" and "ultra" (do not know what they mean but it does not matter). Not sure what other manufacturers are quoting but whatever figures they use, you can just ignore them. Contrast Ratio is not the only item that affect the quality of the picture and in any case, it makes no difference in the real world for watching movies.

(Plasma TV has better Contrast Ratio than LCD normally by virtue of the technology employed so there is less number games for this in Plasma TV specs.)

Another specification is harder to classify, that of Response Time. This figure used to be quoted frequently earlier (especially for gamers) but not so much now simply because the technology for improving the response time of LCD has more or less reached the limit. This item measures how fast an LCD pixel can change state so the smaller figure the better. This used to be in 10's of milliseconds but now it is like 5ms or down to 2ms for some models. Anything 5ms or below should be OK for normal use and in practice the difference is not very noticeable after that. A slow response time will result in motion lag, smearing or trailing effect for fast moving objects in action scenes or sports. (In reality, there is also no agreed standard on how this should be measured and quoted by manufacturers but for simplicity, we assume that this is done more or less similarly and the figures should be used just as a guide; anyway, the discrepancies are not as great as those seen in the Contrast Ratio figures.)

In order to improve the response time, manufacturer is now resorting to increase the refresh rate of the TV to give them another opportunity to play the number game of higher is better. The original refresh rate used is 50Hz (for PAL land like Europe and Malaysia) and 60 hz (for NTSC land like USA and Japan) and newer LCD TV have double or 4 times this to 100Hz or 200Hz (or the corresponding 120Hz and 240Hz for USA and other NTSC countries). The average human eye can discern the improvement from 50 Hz to 100 Hz (or 60 to 120Hz) but the next improvement to 200Hz (or 240Hz) may not be so apparent to some. The newer LED TV are pushing this even further to 400Hz (or 480Hz) but it is doubtful if the normal human eye can see the difference but it does help manufacturer to sell more of these TV sets and make a better profit. Manufacturers are using different terms for these higher refresh rates to attract customers, such as TrueMotion, MotionPlus, MotionFlow, Natural Motion, etc to give the impression that their technology will enable the HDTV to display smooth motion.

Each manufacturer uses a different technology to implement the higher refresh rates so results will be different and some are more effective then others. In addition, a lot depends on the source material itself so if it is bad, no amount of refresh rate will improve it and it may even show up the weakness more. Thus the increase from the standard refresh rate to the higher rates may or may not be a visible improvement for some brands. To really compare, you must play the same source material on two different sets and watch them side by side. If there is no noticeable improvement, go for the lower refresh rate model which is usually the cheaper one. Again, use your eyes as the judge.

In summary, you should totally ignore the Contrast Ratio figures. For the Refresh Rate, you can compare the figures from different manufacturer up to a point as a guide as higher figures are hard to discern visually in real life. This will also vary from model to model. The best is to use your eyes as the judge, not the figures produced by the manufacturers as they are there to impress and sell their products. A good image is not due to just one or two items of the specs but it is a complex mixture of many other factors.

In fact, a finely calibrated entry level HDTV will give a better viewing experience than a badly calibrated high end unit. As an analogy, a well-tuned Proton will perform better than a badly tuned BMW. OK, maybe this is stretching it a bit but I think you get the idea!

Ronald Kwok

Monday, December 13, 2010

HDTV screen size and viewing distance

If you have decided on the type of HDTV that suits you, the next big question will be the size. The general answer will be to get the biggest screen size that you can afford. The only caution here is that make sure you have enough space to view your HDTV at a comfortable distance from the front.

A few general facts on the HDTV screen size. TV sizes are always quoted using the length of the diagonal across the screen. For HDTV, many advise that 32" is a minimum size for your bedroom or those with space constraint and 40" as a minimum for a normal living room. If you are getting a HDTV to replace your existing CRT TV, do not get one with the same size. This is because normal CRT TV has an aspect ratio of 4:3 while HDTV has an aspect ratio of 16:9 and for the same height, the new TV is wider than the old TV or we say the new TV is widescreen and the old TV is squarish. Thus the same image will look smaller on the new TV and to get the same size picture (i.e. same height for the 4:3 picture) on the new TV, the screen has to be bigger. As a very rough rule of thumb, multiply the old screen size by 1.2 to get the equivalent new screen size.

For example, old 27" x1.2 =32" and old 32"x1.2=38". Since the HDTV only come in certain standard sizes, take the next higher one if you don't have an exact match after your calculation. Thus replace your 32" CRT TV with a 40" HDTV. For the budget conscious, the price increases as the screen size gets bigger but an exception may be for older or discontinued models. A 40" HDTV may sound and look big initially but after a while, may users feel that they should have bought a bigger set after the thrill of watching HD movies. Hence the early advise of getting the biggest set that you can afford.

However, the bigger the size of the set, the bigger the size of each individual pixel so a 60" set will look blockier than a 50" set at the same viewing distance. Thus you need to sit further away to watch a bigger display. The general advice is that the maximum distance is 2.5 times the size of the screen (always quoted as the diagonal across) so for a 40" screen, this will be 100" or almost 8 and a half feet away. Personally I find this a bit too far away. Some give the minimum distance as 1.5 times the size of the screen so for the same 40" example, this will be 60'' or 5 feet away. Thus you can sit anywhere from 5" to 8" away for a 40" HDTV to enjoy your show. This is just a rough guide and you can choose to sit any distance you want but if you sit too close, you'll start to see the pixels and if too far, you'll feel like missing the action. The choice is again personal preference and comfort.

I have mentioned in my earlier post that LCD TV has generally a more limited viewing angle when compared to Plasma TV. Thus the height of mounting the TV will be more important in the case of the LCD. So apart from strain necks if the LCD TV is mounted too high, you'll also get a poorer image. You may have to rearrange your furniture and wall decor to suit your new HDTV to have the best seat in the house.

Related to the size of the HDTV is the resolution that boils down to what the marketing guys call Full HD or HD Ready. By definition, the maximum HD resolution is 1920x1080 pixels and the minimum is 1280x720 pixels so Full HDTV has a resolution of 1920x1080 and HD Ready has less than that, usually with 1366x768 pixels for LCD and only 1024x768 for Plasma. They are HD Ready not because they can be upgraded to full HD but that they are ready to accept Full HD materials and downscale them to display on their lower resolution screens. For LCD TV, most models are now Full HD except for a few 32" and below. In the case of Plasma TV, quite a number are HD Ready only even up to size of 50" and you should check the specs carefully if this is important for you. However, experts say that you cannot really tell the difference if they are viewed at the correct distance, especially those of smaller screen size. But if the price difference is not much, you might as well go for Full HD or you may feel uncomfortable afterwards. But if budget is a real issue, get a HD Ready as it is good enough. Again, let your eyes be the judge.

So after picking the right size HDTV for your room, you would have completed your choice but only if you do not have other requirements or fussy about inputs/outputs, refresh rates, contrast ratio, etc. These will be discussed in the next post.

Ronald Kwok

Saturday, December 11, 2010

LED TV - new kid on the block

A newcomer to the HDTV scene has made its presence felt recently and confused the choice of HDTV a little, this is the LED TV. Strictly speaking, LED TV is still basically LCD TV with LED for backlighting instead of fluorescent lights in the normal LCD TV. So instead of calling them LED-backlit LCD TV (the proper name), the marketing guys just call them LED TV. True LED TV where actual LED's are used as the display is called OLED (Organic LED) but these are not yet available commercially. Here I will also use the term LED TV even though they are not really such.

That was how these LED TV got started but manufacturers have now made a variation to this to cut down the cost. Instead of having the LED lighting at the back (normally called full array LED), they place the LED along the sides of the LCD panel for the lighting and this is termed LED edge-lit LCD TV but again the marketing guys are not too keen to tell the difference and this is also simply called LED TV. Consumers are also not bothered as long as the HDTV screens look good.

In theory, the full array LED can perform better than edge-lit LED (and more expensive) since each pixel on the LCD screen can be control individually by the LED array while the backlighting by edge-lit LED is not so precise. Thus the outer edge of the screen may appear brighter. However, with improving technology, the difference may not be so obvious.

The main advantage of these LED TV over the normal LCD TV is that they are thinner and consume less power. Manufacturers also claim that LED TV produce better image with better contrast, blacker black and faster respond time compared to LCD TV, even approaching that of the Plasma. How much better varies from model to model but generally the higher the price, the better. On the other hand , some viewers find the LED TV to be too sharp and too bright and thus unreal and unnatural; a little too perfect since after all we live in an imperfect world!

The main disadvantage of LED TV at the moment is of course, the price, as it is the most expensive among the three flat-screen TV of Plasma, LCD and LED. But price will surely drop as more LED models become available. However, they still cannot compete with Plasma in the viewing angle.

Knowing the differences may help in your decision but finally whether you prefer a Plasma, LCD or LED TV is in the end a personal choice and so let you eyes be the judge. There are other features that you may want to consider, but these may or may not be critical depending again on personal preference.

Maybe I should just mention here that the latest marketing hype in HDTV is the 3D TV. Since this is priced beyond the reach of the masses and currently has not many source material to play with, we will not discuss them here.

My next post will be on deciding screen size. So stay tuned.

Ronald Kwok

Thursday, December 9, 2010

Which type of HDTV - Plasma or LCD?

(Information is compiled from Internet sources such as Wikipedia, CNET, etc. but opinions are my own.)

The heart of the HD world is undoubtedly the HDTV and this is very often the first HD item to be purchased. This blog will hopefully point you in the right direction when choosing a HDTV.

Choosing a HDTV is not that confusing or difficult so we'll break it down to small bits so it will be easier to make a decision. There are basically two main types of flat-screen HDTV, the earlier Plasma TV and the latter and now more popular LCD TV both employing very different technologies. For those interested in the technical details, refer to Wikipedia.

Below are some general information about the main advantages between the two as a guide but this may vary from model to model and subject to change with new improvements from time to time.

Plasma - better Viewing Angle, better image quality (blacker black and better contrast), superior motion resolution for fast action.

LCD - no screen burn-in effect, lower power consumption, matte screen reflects less light, can get sizes below 40", a wider choice of manufacturers and models, more common PC connectivity, most models are full-HD.

A little more detail on some of the items mentioned.

*Viewing Angle - For Plasma, image will look the same at all viewing angles but for LCD, image will look faded or washed out if viewed at an angle from the sides or from top and bottom.

*Screen burn-in. An image permanently etched onto the screen, say when you pause a picture for too long. This will never happen for LCD but for Plasma, there is a possibility but not likely for normal usage.

*Motion blur and trailing - negligible on Plasma but noticeable on LCD for fast action movement e.g. a soccer game or other fast sports. Newer, fast LCD models has reduce this somewhat.

*Image quality. For purists, Plasma has better overall picture quality, especially blacker blacks and more natural colours. But many prefer the bright and saturated "larger than life" colours of LCD.

*Glossy and matte screen - Plasma glass screen reflects more light so not that good when view in a bright or well-lit room. LCD will look better than Plasma in these conditions.

*Power efficiency. LCD TV consumes less power than a Plasma of the same screen size, due to the different technology employed. Also LCD is less bulky than Plasma.

*Screen size. If you need a screen size of 32" or less, you can only get an LCD. Plasma is available from 40" or 42" upwards.

*PC connectivity. If you need to connect a PC to the HDTV, you'll be able to do it for most (if not all) LCD TV. This is less common for Plasma TV so need to double confirm if this is one of the usages.

*Full HD or HD Ready. Most LCD TV models are Full HD with resolution of 1920x1080 pixels while many Plasma TV at the lower end are just HD Ready with resolutions of 1366x768 pixels or 1024x768 pixels. (I am very surprised by this as I thought all Plasma TV are Full HD.) According to many reviewers, it is difficult to see the difference in practice so it is more psychological that Plasma is inferior in this area. And because of the lower resolution of Plasma TV (except for the higher end models) and possible image burn-in, it is better to choose an LCD TV if PC usage is intended.

*Choice of Manufacturers. Plasma TV brands are limited to Panasonic, Pioneer, Samsung, LG and NEC. LCD TV are also produced by them in addition to Sony, Sharp, Toshiba, Philips, Sanyo and many others. Thus there is a much wider choice in LCD TV.

In the early days, you get get Plasma in larger screen size and cheaper than an LCD for similar screen size but this may no longer be true as LCD are available now in comparable sizes with prices similar to Plasma. The lifespan of Plasma and LCD are about the same so there's little to choose here. It would seem that LCD TV is more popular than Plasma TV maybe because there are more manufactures and more models to choose from. In addition, more people are attracted to the bright, saturated and flashy colour of the LCD TV (some call this artificial, but hey, are we not attracted by artificial boob jobs and the like?)

So deciding between LCD and Plasma will depend on the primary purpose of your HDTV and the environment it will be used in but in the end it boils down to personal preference. Nothing like seeing for yourself and as long as you like what you see, then go for it after considering the major differences mentioned above if they are important for you. And of course get one within your budget.

My next post will be on other factors to consider like screen size and other features.

Ronald Kwok