Cheap HDTVs

High Definition TV is becoming more and more popular. The quality of the image really stands out when compared with old standard TV resolution. In addition, we all like to play our videogames on a HDTV, because they just look much better. Then there are also blu-ray players (and let’s not forget that the Playstation 3 can play blu-ray discs), among other things.

Nevertheless, when it comes to buying an HDTV, many people get baffled by the technical specifications. What does 11920×1080p25 mean? And is it better than a HD TV that is 1080i30? Does it matter?

Aside from the ones that actually like getting into specification, most people ignore what these parameters mean, and which ones are better. Some of them just get the biggest HD TV they can afford. Others think that bigger numbers mean a better HDTV. Some just get the cheapest HDTV they can get for a specific size.

In reality, the best HD TV is the one that suits your needs better. But in order to shade some light about the nature of HD TVs, let’s study one parameter in particular: the scanning system of a HD TV.

The scanning system is one of the most obscure (for the regular person) specs of a HD TV. There are two systems, progressive scan and interlaced video. The reason why scanning systems are so obscure is because they are usually represented by a single letter: p for progressive scan, and i for interlaced video.

And what are progressive scan and interlaced video? They are the ways that your HD TV uses to render images. Of the two, interlaced video is the oldest technology.

Imagine a page from a notebook with horizontal lines. Now number those lines from 1 to 20 and imagine that’s your screen. A while ago, the information you could send at a time (bandwidth) was more limited that it is today. So, in order to save it, not all lines were broadcasted at the same time. First, only odd lines were broadcasted, then, a fraction of a second later, even lines were broadcasted. This allowed a good image without increasing bandwidth by much.

Then, when bandwidth was improved through digital compression, progressive scan came to be. In this case, ALL lines are displayed at the same time. This allows for a much better image, especially when dealing with movement.

So, all other factors remaining equal, progressive scan is better than interlaced video. Of course, that’s just one factor among many. But at least you know now what the p in 1080p means.