HDTV explained!

pana.jpgI have been asked by numerous people, numerous times, to explain HDTV. Or said in a better way

"Which flat panel TV should I buy?"

Aspect Ratios:

When you look at your old CRT television it is slightly wider than it is taller. This ratio is described as 4:3. Meaning it is 4 units wide by 3 high. The newer flat panels (and even some CRTs) came out in the wide screen format. This aspect ratio is described as 16:9. This is the standard for most flat panel screen, whether they be LCD or Plasma. The 16:9 ratio is closer to the theater experience, that allows you to see all of the picture.

Screen Resolutions:

Most of us have computers. And most of us are familiar with screen resolutions of 800 x 600 or 1024 x 768. This was the number of pixels tall and wide. With TV’s there is a new form of measurement, 480i, 480p, 720p, 1080i, 1080p. Let’s start with your old CRT. Most CRT TVs are either 480i or 480p. The i stands for interlaced and the p stands for progressive. CRT TVs use an electron gun to scan lines onto the screen. Interlaced means every other line. So if a TV says it supports 480i, then at any instant in time there are actually 240 lines on the screen, followed by 240 lines a split second later. It happens so fast that, you can’t really see it, but some notice the flicker. Next is 480p. This was a standard that we started seeing in DVD players a few years ago, when they say they are progressive scanning DVD players. This means there are 480 lines on the screen at one time. You may notice that some TVs, both CRT and flat panel are called EDTV. This stands for Enhanced Definition TV. These TVs will show a maximum of 480p, and are not to be considered HDTV. Make sure you don’t get fooled by the lower pricing on EDTVs. These will not give you the HD experience.

HDTV starts at 720p and up. This means there are at least 720 lines on the screen at one time.  HDTV also includes 1080i and 1080p. This is where most people get confused. Recently many of the new TVs have come out with 1080p and have started calling themselves Full HD or True HD. This is just marketing. The main thing to keep in mind, is that HD content from broadcasters (either cable or satellite) is available in 720p or 1080i. To get 1080p content, you need to have a Xbox 360, Playstation 3, HD-DVD player or Blu-ray player. When you talk about screen resolutions, similar to the computer screen resolutions, here is how it works.

The second number will tell you the maximum HD resolution you can have. (keeping in mind the difference between i and p). For example, if you look at the most common resolution of 40"-42" flat panels, you will see them stated at 1366 x 768. So looking at the second number, this screen would allow for 720p or 1080i. (remember, i scans every other line). But this screen could not do 1080p as the resolutions for this format is 1920 x 1080. If you buy a panel today that can only do 1080i, it doesn’t mean you are behind the times. Think of it as a starter system. The pricing on 1080i systems has dropped tremendously over the past 3-4 months. 1080p systems, are new and therefore the pricing is higher and will be some time before they drop down.

Consumer vs. Commercial Flat Panels:

Lately consumers have started to see, what many manufacturers refer to as their commercial or professional series, flat panels. These units are the same display, but with our the TV tuner or speakers attached. At first many think that these units are a bad idea But when you really think about it, if you connect to satellite or cable, you don’t need  tuner as the set top box supplies one for you.** Plus, if you have a surround sound system, there is no reason to use the speakers attached to the system. There is no difference between the picture quality between the consumer and commercial systems as they use exactly the same glass. Many times by not having the tuner or speakers you are getting the same quality at a better price.


Most flat panels today have a number of connections at the back. Which one to use will depend on what you are hooking up to the set. You should know, that in order to get HD resolution you have 3 choices. Component (red, green, blue cable), DVI or HDMI. Component is an analog cable that is the same on many DVD players. This will allow you to get up to 1080i on your flat panel. DVI and HDMI are digital cables. They will allow you to get up to 1080p. The video signal on both cables is the same. With HDMI, they add the audio signal on the same cable. I am always confused as to why someone would want to run an HDMI cable to their flat panel. First, they are expensive. Some are as high at $200 for a 4 ft. cable. Second, most people who have a flat panel TV, will have spent some money on a surround sound system. Granted the speakers that come with today’s flat panels are much better than the old CRT speakers. They don’t come close to the quality of your surround system. So my recommendation is to go with component or DVI and put the sound through your surround system. Use the menu on your TV to turn off the speakers that are attached to your TV. I can’t stress enough, the cables you should not be using are the composite, which is the single yellow RCA type plug. Or the small 5 pin S-video cable. Neither of these 2 will give you the HD resolution that you paid for.

Plasma vs. LCD:

A year ago plasma was the leader for large flat panel TVs. For a few reasons, better contrast (blacker blacks), cheaper and a wider viewing angle. LCD is making tremendous strides, and for a panel under 40 inches, I would probably go with LCD. But for greater than 40 inches it is still plasma that has the biggest bang for the buck. This is changing and could be the other way around by the end of this year. The old myth of plasma burn in has been fixed by most mainstream manufacturers by a number of methods. It really comes down to a personal choice. If you have a home theater environment, then plasma is probably the way to go. If you have a bright room, and you will be watching the TV straight on, then LCD would be a better choice. At the end of the day, put the 2 screens side by side and see which one has the better picture.

If I have missed anything or you still have questions, leave a comment at I will add to this explanation.

June 2009 Update:

Today, June 12th the US is converting their Over the Air signals to digital. Now, for most people this is a non-issue, as many are using some form of set-top box that is connected to a cable company or a satellite company. For these people there is no change. But there are many in rural areas who will be affected, as they receive their signals exclusively via antenna. At the same time this offers opportunity for some located near urban centers to receive free HDTV signals.

The reasons for the changes to digital are complicated. Basically they are running out of room on the frequencies that broadcast signals, so they need to shuffle some things around. It also helped to push broadcasters into the digital era of HDTV.

**The new opportunity lies for those within 30-50 miles of an urban center with a wide selection of TV stations. You now have the opportunity to get rid of you cable or satellite provider, or at the very least, reduce the amount of money you are paying. If you are close enough you can install an antenna to pick up the signals for your HDTV. Keep in mind that you will need a TV with a digital tuner  (look for ATSC) to do this. Yes I know, this contradicts what I said above with regards to commercial HDTVs. A friend of mine discusses this in this post.It is easy to do and best of all it is free. It will be interesting to see how this impacts HDTV signal providers over the coming months. I would suspect that most would not know about it and will go with cable or satellite.

18 thoughts on “HDTV explained!”

  1. Kevin, excellent information. You cleared up HDMI for me ; well mostly. The only thing I don’t get is this – Everyone is raving about HDMI as it is one cable for both video and audio. What confuses me, is how do you get the audio from the source into your surround system and then back to you TV? I have seen, I think 1 home theater tuner that supports HDMI and it was rather cost prohibitive to put it politely, and none of the legacy equipment supports it that I know of unless there is some sort of adapter.

    Am I missing something here?

  2. No, you haven’t missed anything. You would need an receiver with HDMI ports. HDMI cables goes from your set top box, and your DVD player to the receiver. Then 1 HDMI to your TV. The receivers are very expensive for this.

    You can also run either component or DVI to your TV. Then run digital coax or optical to your receiver.

  3. Can I have 3 HDMI components running into a 3 way HDMI switch box, out of the swicth box into a 4 way HDMI distribution amp, out of the 4 way distribution amp into 4 * 8 way HDMI distribution amps to feed to 32 TV’s?

  4. Clyde, there are 2 things to consider. First is signal strength. Will there be enough to run that many TV’s?? Only way to find out is set it up. Second is HDCP. If you are going to run any copywrited content you will not be able to distribute the picture to that many TVs.

  5. Great Article!! 1 question, I am going to be getting HD satelite box (Dish network), they say it has a Dvi connector on the back, but by the pic I have seen it only has a Hdmi connector, my 57in. TV only has a Dvi connector currently. I also use a fiber optic cable to my surrond sound, I see at Fry’s they sell a Dvi to Hdmi cable is this the best way to go?

  6. Yes, you can get a cable or some places just sell the connector converter for HDMI to DVI. I would doubt that the HD box only has a HDMI connector though, as it is too soon for manufacturers to be only HDMI as there are not enough peripherals to support HDMI yet.

  7. Kevin – I just purchased an LG 42LC7D LCD HDTV and it works awesome. The picture is great. The only thing I’m a little concerned about is the running lines that start either at the bottom of the screen or middle of the screen and then run up towards the top of the screen. It’s not really noticeable unless you notice it and then it can stand out each time it does it. It is something that I can live with for the picture it produces, but I didn’t really expect to see the lines like this. It is particularly noticeable when there are dark images on the screen. Any advice on this or is it just standard with a flat screen tv with HD? Thanks in advance.

  8. If you are getting an HDTV signal via a cable box or satellite box, then you should not get these lines on the HD channels. However, if it is a standard definition signal, or you are watching a standard def. channel you may get this. The other thing to check is your cables. Are you using either component, DVI or HDMI. If yes, then you should not get something like this on an HD signal on a HD channel. If you are using all of the HD above, then check your connections into and out of the HD box (cable or satellite) and lastly try a different cable.

  9. Sounds like you don’t have an HD signal or you are not watching the HD channels. You need to upgrade to either a cable or satellite HD feed. That will give you the full screen HD, non-stretched picture. If you are watching a standard signal you will get all the things you mentioned in your post.

  10. Yes this could be a case of you can’t have your cake and eat it to. Chances are the free cable you are getting now is standard definition.
    The only way you could get free HDTV reception is if you live close to the US Canadian border and there is a large US city on the other side. Then you may be able to receive some HDTV signal over the air (OTA) with an antenna. But the most I have ever heard anyone getting are 3-5 stations.

  11. Thank you very much for comprehensive information. I have 1920×1080 LCD panel sharp 65gd1e. It has an external TV tuner which seems to be capable of 1080i. I understood from your article that 1080 panels should be capable of 1080p. Will I be able to get 1080p by changing the original tunerto a newer one? Or turning the question to it’s substance – is every 1920×1080 panel capable of doing 1080p? Thank you very much for your time and sorry for my English – it’s not my mother language.

  12. Right now you can only get 1080p from Xbox, PS3, Blu-Ray DVD and HD-DVD. There are no TV signals broadcast in 1080p yet. Most are 1080i and some are 720p. It is expected to be a couple of years before signals will be broadcast in 1080p.

  13. I have a Sony Bravia-it’s great, but I have 1 question. I have upgraded to high def cable box and I have the cable from the box into the tv. I also have a high def cable wire. The back of the tv and the cable box also has a green, blue, red (i think) connections. Would it upgrade my picture to have this cable in addition to what I already have.


  14. You should use the green, blue, red cable, or the HDMI cable. (looks like a big USB plug). Either will give you the HD image you are looking for. You only need 1 cable. Adding a second cable would not do anything to improve the picture.

  15. Just recorded my interview with Global TV’s Sean O’Shea about the digital transition and my experience canceling cable and putting up an OTA antenna for HDTV. It’ll be on Friday June 12, 2009 at 6:30 or so, Global TV.
    I hope it turns out ok! 🙂
    Thanks for the reference to my blog post Kevin.

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