Chesapeake Home Theatre & Hi-Fi

Larry Dent is the owner of Chesapeake Home Theatre & Hi-Fi.

These articles were written for the Islander Weekly.

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Larry's Tech Talk

Say You Want a Resolution

If you’ve purchased or shopped for a new LCD or plasma TV in the past few years, you probably have seen the numbers, 1080i, 1080p, 720p, 480i, 4:3, 16:9. What does it all mean?

The invention of high definition TV has made things a little complicated. Back in the day we all had an antenna or rabbit ears and whatever our TV received was what we watched. Cable and Satellite service gave us more channels. And then we all saw a picture improvement with the DVD. But technically, if you watch a DVD, you’re actually seeing standard definition images. Yes, the DVD was an improvement in resolution, but not as good as high definition as we know it today. OK dude, so what are all of those numbers about?

Those numbers refer to the video resolution that a TV is capable of displaying. Specifically, I am referring to the pixel count. You won’t see pixels a few feet away from the screen, but if you get up close, take a look at the screen. Those little square dots are called pixels. And of course with more pixels, higher definition images are possible. When you move back from the screen the dots appear to merge together and you hopefully have a sharp, bright picture.

DVD players gave us a much improved picture with a format called 480i. If you’re a real Geek, that equates to 704 lines of pixels stacked 480 times. The “i” stands for interlaced, which actually means that there are 240 alternating lines of pixels scanned every 1/60 of a second. We all like to think that the higher the number means the better the resolution. That is true to some extent, but the suffixes “i” and “p” are important too. As I mentioned, “i” stands for interlaced. The suffix “p” stands for progressive. Progressive formats are not interlaced. So a format like 720p, actually has more information than 1080i.

To the human eye, 720p and 1080i will look very much alike. You would have to be very well trained and have phenomenal eyes to be able to see the difference. That brings us to the highest resolution currently available, 1080p. Believe it or not there is not much 1080p video content which we have access to. But if you want to be sure you are seeing 1080p, connect a BluRay player with a “native” BluRay disc and you will have 1080p.

Technology is pushing the limits of the human eye. I’ve read that if you stand 8 feet back from your TV, most people cannot tell the difference between 720p and 1080p. This is true particularly with smaller TVs. If you have a 32” 1080p TV, you probably could have saved a few dollars by buying a 720p set. Almost all broadcasts are in either 720p or 1080i.
Yeah Larry, but what about those “black bars” I see on some channels. I bought a 50” TV and I want a 50” picture! Those bars on each side have to do with something called “aspect ratio”. Standard definition is broadcast in a 4:3 aspect ration. If you think about it, 4:3 is an almost square ratio. Older TVs were square in shape for that very reason. Today’s hi-def TVs are rectangle to accommodate the 16:9 aspect ratio. So, if you see the bars, you are watching square video content on a rectangle TV. Most TVs have a button on the remote control to remove the bars. But by forcing the picture to fill the rectangular screen you will notice some distortion. People may appear to be shorter and gained weight as a result. As more and more programming becomes high definition, the 4:3 aspect ratio will probably fade away.

OK, let’s recap the numbers, 480i was not bad. 720p and 1080i are excellent and very similar to the human eye. 1080p is the highest resolution available and more noticeable in larger TVs. And set your cable or satellite receiver to the 16:9 aspect ration to watch hi-def shows that fill your new TV screen.

Remember that old Beatles tune? Say you want a resolution?