FAQs
- What is HDTV?
- How Can I Get High Definition Signals at My Home?
- Will an old VHF/UHF antenna receive HDTV signals?
- Should I Buy a Widescreen (16:9) or Regular (4:3) TV?
- The Technical Differences between LCD and DLP?
- The Advantages of LCD Technology
- The Advantages of DLP Technology
- What is Blu-ray?
- Will Blu-ray replace DVDs?
- Will Blu-ray be backwards compatible with DVD?
- Why should I upgrade from DVD to Blu-ray?
- Why there are black bars on HDTVs?
1. What is HDTV?
HDTV, or High Definition Television, is a new set of standards for television and the quality in which we will watch it. It is the only change that has been made to the television format since we switched from watching black and white to watching color television many, many years ago.
To start off, regular color television is scanned at 480i, which means there are 480 vertical lines that are scanned in an 'I'nterlaced format. This means that at any given time, only half of the picture is on the screen at a time. While one frame will only display the odd lines (1, 3, 5), the next frame will only display the even lines (2, 4, 6). This happens so fast that the human eye is tricked into thinking that it is only seeing one picture.
This is contradictory to progressive scanning, which means each frame is displayed all at one time. Instead of interlacing the lines, each frame is displayed as you would guess, being line 1, line 2, line 3, etc. The end result is a much sharper image and looks much better. Although the difference in an interlaced signal and a progressive signal is the way the picture is scanned, it does have a big difference on the resulting image.
Now true HDTV signals are signals that are broadcast in a format of 720p or 1080i. 720p means that there are 720 horizontal lines that are scanned progressively and 1080i means there are 1080 horizontal lines that are scanned in an interlaced format. Although there is a big difference in the number of horizontal lines, the fact that 720p is progressive and 1080i interlaced means that the resulting pictures are very similar.
2. How Can I Get High Definition Signals at My Home?
There are three ways of receiving HDTV broadcasts, though depending on where you live satellite might currently be your only option...
Cable: If your local cable provider currently supports HDTV then you can receive those signals from them. Pricing and the number of channels they carry depends on where you live. You will need to get a HD decoder box from the cable company to watch these signals.
Over The Air: Over The Air means setting up an antenna and receiving those channels from local broadcast towers. If you are in a large metropolitan area then chances are good that you can already receive free HDTV over the air. You will need to get a separate decoder box to watch these signals and in many cases will have to mess around with the setup a bit before everything is running smoothly.
Satellite: Almost anyone can receive HDTV via a satellite company and all satellite companies currently carry high definition channels. You will need to get a special HD decoder from the satellite company to watch these signals and you usually will have to pay a small price increase for this service as well.
3. Will an old VHF/UHF antenna receive HDTV signals?
A regular VHF/UHF antenna will work for receiving HDTV signals. However, even though a regular old VHF/UHF antenna will pick up HDTV signals, you might need a newer antenna with a pre-amp to actually receive the channels. This will depend on three things: (1) How far you live from the local broadcast towers (2) How powerful the signals are that they are actually broadcasting, and (3) What your local terrain is like: Do you have large buildings, big trees, foothills near you? The worse off you are with the above three items the better of an antenna you will need.
4. Should I Buy a Widescreen (16:9) or Regular (4:3) TV?
A high definition television is 16:9 Widescreen by default. Many companies produce higher resolution TVs that are still in the 4:3 format and market these as HDTVs, though they are not "true" HDTVs. Either way when buying a new TV most people want to know if they should get 4:3 or 16:9. The answer is not as simple. A 16:9 TV is great for watching DVDs and High Definition programming as both are in wide screen formats.
However, all 16:9 televisions will either show grey borders on the sides of SDTV programming or stretch the screen to fill the entire screen. The later makes people and objects on the TV look stretched and often people find annoying. The framing of the picture in grey borders is annoying to some people as well. Which you will use is up to you. This is one of the reasons people are still sticking to regular 4:3 TVs and many times don't make the high definition upgrade.
5. The Technical Differences between LCD and DLP?
LCD (liquid crystal display) projectors usually contain three separate LCD glass panels, one each for red, green, and blue components of the image signal being fed into the projector. As light passes through the LCD panels, individual pixels ("picture elements") can be opened to allow light to pass or closed to block the light, as if each little pixel were fitted with a Venetian blind. This activity modulates the light and produces the image that is projected onto the screen.
DLP ("Digital Light Processing") is a proprietary technology developed by Texas Instruments. It works quite differently than LCD. Instead of having glass panels through which light is passed, the DLP chip is a reflective surface made up of thousands of tiny mirrors. Each mirror represents a single pixel. In a DLP projector, light from the projector's lamp is directed onto the surface of the DLP chip. The mirrors wobble back and forth, directing light either into the lens path to turn the pixel on, or away from the lens path to turn it off.
In very expensive DLP projectors, there are three separate DLP chips, one each for red, green, and blue. However, in DLP projectors under $20,000, there is only one chip. In order to define color, there is a color wheel that consists of red, green, blue, and sometimes white filters. This wheel spins between the lamp and the DLP chip and alternates the color of the light hitting the chip from red to green to blue. The mirrors turn on and off based upon how much of each color is required for each pixel at any given moment in time. This activity modulates the light and produces the image that is projected onto the screen.
6. The Advantages of LCD Technology
One benefit of LCD is that it controls red, green, and blue independently through three separate LCD panels. That means you can adjust brightness and contrast of each color channel individually. In LCD projectors with good controls on board, this can enable the projector to achieve very good, and sometimes excellent color fidelity. In most single-chip DLP projectors, color is fixed and defined to a large degree by the physical color wheel and the color temperature of the lamp which changes over its usable life. So while DLP technology has gotten much better at reproducing accurate color, good LCD projectors still have a slight performance edge in this area.
LCD also delivers a somewhat sharper image than DLP at any given resolution. The difference here is more relevant in data than in video. This is not to say that DLP is fuzzy--it isn't. When you look at a financial spreadsheet projected by a DLP projector it looks clear enough. It's just that when a DLP is placed side-by-side with an LCD, the LCD typically looks a little bit sharper in comparison. However, it isn't something you'd notice except in a side-by-side comparison.
A third benefit of LCD is that it is more light-efficient. LCD projectors produce significantly higher ANSI lumen outputs than do DLPs with the same wattage lamp. In the past year, DLP machines have gotten brighter and smaller--there are now DLP projectors rated at 2000 ANSI lumens, which is a comparatively recent development. Still, LCD competes extremely well when high light output is required. All of the portable light cannons in the 15 lb weight class putting out 3000 ANSI lumens or more are LCD projectors.
7. The Advantages of DLP Technology
There are several unique benefits that are derived from DLP technology. One of the most obvious is package size. Since the DLP light engine consists of a single chip rather than three LCD panels, DLP projectors tend to be more compact. All of the current 3-pound miniprojectors on the market are DLPs. Most LCD projectors are six pounds and up.
Another DLP advantage is that it can produce smooth, high contrast video. DLP has been well-received in the home theater world primarily due to two video quality advantages - better contrast and the lack of pixelation. Earlier generations of LCD projectors were notorious for their inability to generate acceptable black levels and contrast, and to resolve subtle shadow details. Blacks on LCDs looked gray and shadows appeared muddy and indistinct. In comparison, DLP projectors did a much better job.
8. What is Blu-ray?
Blu-ray, also known as Blu-ray Disc (BD) is the name of a next-generation optical disc format. The format was developed to enable recording, rewriting and playback of high-definition video (HD), as well as storing large amounts of data. The format offers more than five times the storage capacity of traditional DVDs and can hold up to 25GB on a single-layer disc and 50GB on a dual-layer disc. For more general information about Blu-ray, please see our
9. Will Blu-ray replace DVDs?
Yes, that's the expectation. The Blu-ray format has received broad support from the major movie studios as a successor to today's DVD format. In fact, seven of the eight major movie studios (Disney, Fox, Warner, Paramount, Sony, Lionsgate and MGM) have released titles in the Blu-ray format. Many studios have also announced that they will begin releasing new feature films on Blu-ray Disc day-and-date with DVD, as well as a continuous slate of catalog titles every month.
However, the two formats (Blu-ray and DVD) will most likely co-exist for quite some time until HDTVs become more widespread.
10. Will Blu-ray be backwards compatible with DVD?
Yes, several leading consumer electronics companies (including Sony, Panasonic, Philips, Samsung, Pioneer, Sharp and LG) have already demonstrated products that can read/write CDs, DVDs and Blu-ray discs using a BD/DVD/CD compatible optical head, so you don't have to worry about your existing DVD collection becoming obsolete. In fact, most of the Blu-ray players coming out will support upscaling of DVDs to 1080p/1080i, so your existing DVD collection will look even better than before. While it's up to each manufacturer to decide if they want to make their products backwards compatible with DVD, the format is far too popular to not be supported. The Blu-ray Disc Association (BDA) expects every Blu-ray Disc device to be backward compatible with DVDs.
11. Why should I upgrade from DVD to Blu-ray?
The simple answer is HDTV. If you've ever seen high-definition (HD) video on an HDTV, then you know just how incredibly sharp the picture is and how vivid the colors are. In fact, HD offers five times the amount of detail compared to standard-definition (SD). The problem with today's DVDs is that they only support SD and don't have the necessary storage capacity to satisfy the needs of HD. That's where Blu-ray comes in, it offers up to 50GB of storage capacity and enables playback, recording and rewriting of HD in all of the HD resolutions including 1080p. The format also supports high-definition audio formats and lossless audio.
In addition to the greater video and audio quality, the extra storage capacity also means there will be plenty of room for additional content and special features. This combined with the new BD-J interactivity layer adopted by Blu-ray will bring the menus, graphics and special features to a whole new level. For example, you will be able to bring up the menu system as an overlay without stopping the movie, and you could have the director of the movie on the screen explaining the shooting of a scene while the scene is playing in the background. The advanced interactivity combined with the networking features of Blu-ray will also allow content producers to support new innovative features such as downloading extras, updating content via the web, and watching live broadcasts of special events.
Thanks to the greatly enhanced HD video and audio quality as well as the advanced interactivity and networking features, Blu-ray represents a huge leap forward in the DVD viewing experience and will offer consumers an unprecedented HD experience.
12. Why there are black bars on HDTVs?
It never fails, one of the first thing just about every new HDTV owners asks is; why are there black bars on my new widescreen TV? And this is the reason why just about every HD discussion forum has a sticked thread at the top of the forums explaining why this still happens. So in this addition of HD 101, we figured we'd have our go at trying to give a simple answer to an age old question. The most basic explanation is because the image you want to watch isn't the same shape as the your TV. Of course that seems too obvious and now you're thinking; but why not, they're both widescreen? But rather than getting into the why are there so many shapes -- called aspect ratios from here on out -- we'll show you the various formats and the different ways they might be displayed on your HDTV.
Just about all HDTVs have an aspect ratio of 16x9, or 1.78:1. This basically means that if the screen was 16 inches wide, then it would be 9 inches tall. This is much wider than older TVs which were 4x3 or 1.34:1. Things would be complicated enough if there were only two aspect ratios, but life is just not that simple. The most obvious examples that break out of these two are the ones used for most films; 1.85:1 and its wider brother 2.35: -- the only other one worth mentioning here is usually used for computer monitors, which is 1.6:1. Now It is pretty obvious that when we watch 4x3 content on a 16x9 HDTV -- or vica versa -- that we'd see black bars to make up the difference. But obviously this isn't the only scenario, because not only does it matter what the original aspect ratio of the material is, but it also matters what it was optimized to be displayed on.
4x3 on a 16x9 HDTV
Pillar box
We'll start out with an easy one. We've all seen this right, turn on your brand new HDTV switch to an SD channel and you are greeted with black bars on each side to make up the difference. Sure it isn't ideal, but at least the part of the image that is full doesn't look out of wack.
Stretching
Ok, so you paid all that money for a TV, you want to use up the whole thing right? So you hit the stretch button and now you can see how fat this women just got because it's all stretched out. Although this might seem like a good idea at first, the fact that everything looks out of proportion starts to get to most people.
Non-linear stretch
If you hate black bars, then at this point you're thinking, "now we're talking." Sure it seems great at first because her face doesn't look bad at all. But just wait, because as soon as the camera pans from right to left you might just lose your lunch. Just stretching the edges seems like a great idea because most of everything you care about is in the middle, but it isn't worth it either.
Cropping
In this example, the image is simple cropped on the top and bottom -- some TVs call this zoom because the image is zoomed in on, which effectively cuts off the top and bottom. At least with this one though you won't feel sick when the camera pans and no one looks fat, but who knows what you might be missing. Just look at the logo for a glimpse of how much of the image is lost.
A combination of two
We don't have a good example of this one, so we'll just explain it. Basically this is what some channels like TNT HD do. The image gets cropped and at the same time a non-liner stretch is performed. On top of this, sometimes little black bars might be left on the sides which will either be not noticeable or won't be seen at all since most TVs have a little overscan. This is without a doubt the most tolerable of all the modified ways to show 4x3, but for us, when we do watch 4x3 content, we'd just assume see the black bars.
Widescreen optimized for 4x3 and then displayed on a 16x9 HDTV
This is the most annoying example ever. Here we have a widescreen image optimized for a 4x3 TV and then displayed on a 16x9 TV. Believe it or not this is how all early DVDs were done, but luckily it's hard to find new ones like this. There really isn't any excuse for this these days, but it isn't hard to find. The only consolation is that it is the easiest to deal with, because all you do is activate the crop or zoom feature on your TV to eliminate the black bars. Of course the image will probably still look terrible since it isn't HD and now it's been zoomed.
2.35:1 framed in 16x9
This is the best example that gets new HDTV owners in a tizzy. Here they are trying to enjoy their brand new HDTV and now they are faced with the realization that even though they thought life with black bars was over, it isn't. This can be avoided very easily by using the crop feature, and since the bars aren't that big, most won't notice. That being said there are many out there -- present company included -- that can't stand it when 2.35:1 is cropped to 16x9. So when you see the term OAR used online, this is what they want to see. It basically means, black bars or not, they want to see everything in its Original Aspect Ratio.
1.85:1 framed in 16x9
So these are the examples of why you'd see black bars on your HDTV. Ultimately the black bars aren't the end of the world and in fact they allow you to enjoy the image the way it was intended to be consumed. So rather than fight them, just kick back and enjoy the part of the image that is there -- we prefer to think of the image as twice as wide, rather than half as tall. The only other thing we'd like to point out is that HD comes in many different aspect ratios and although content specifically created for HDTVs is 16x9, an old movie shot at 4x3 can have just as much detail as a newer movie can.
