In the high paced techno world that we live in, we are posed with all sorts of technical jargons everyday. One such thing that has caught up a lot of attention recently is HDTV. Having bought an HDTV myself several months ago, I did some research and thought of collating my thoughts on the topic. My friend Srihari deserves a lot of credit since he already did most of the research and gave me the right insights to buying our TV. One of the fundamental misinterpretation that leads to a great deal of confusion about HDTV is the distinction between display technologies and HDTV transmission standard as such. The display technologies that you will hear most often are LCD, Plasma, DLP and the conventional CRT. It is completely different from the HDTV standard as such. What it means is that, you can watch HDTV channels on any of the aforementioned display media.
As one can guess, HDTV contains more information about a picture and hence needs more bandwidth. In this context, you shouldnt confuse between aspect ratio and pixel information. As most of us know, HDTV has an aspect ratio of 16:9 when compared to 4:3 for a conventional TV. Most people think that, the aspect ratio is the reason why HDTV has better quality, which is blatantly false. Aspect ratio just defines the width to height ratio. It was 1.33:1 (4:3) previously and for HD it is 1.77:1 (16:9). This just means that the screen will be a little wide angled. In a normal TV, the resolution is mentioned in terms of 640×480. This just means that there are 640 pixels in the horizontal column and 480 lines (vertical). You can see that the ratio between 640:480 is 4:3. This could mean that, you can create an HDTV with, say 640:360, it would still obey the aspect ratio rules. Anyway, the standard pixel count for an HDTV is 1920×1080 (around 6.75 times more pixels than a regular TV), and you can see that the number of lines to be scanned has increased from 480 to 1080 as well. There are intermediate points chosen and marketed in the names of EDTV, SDTV etc., Some manufacturers try to take a HD-transmitted data and down convert it to, say 720 lines and market it as HD compatible TVs. When people refer to 480p/480i/1080p/1080i, the p and i mean progressive scan or interlaced scan and the number preceding it denotes the number of lines. EDTV is a nice sweet spot till sometime back since it can provide DVD quality (852×480). When you watch DVD in a HDTV, it just does extrapolation (up-conversion of pixels to fit HD quality) to fill all the pixels. One should also bear in mind that bigger TVs still have the same number of pixels in a row, only bigger. This is the reason why the bigger the TV gets, you should watch it from a distance (8-10x the diagonal size of TV) to have a better quality. Otherwise, you will start distinguishing the pixels.
According to FCC, all TV transmissions should eventually become HD in the next 4-5 years. This deadline has always been a moving target. However, with better display technologies and lower cost, people are already switching in large numbers to HDTV. Needless to say that one of the key thing to be considered before buying an HDTV is its cost to performance ratio. You can get the best performance with LCD/Plasma (L/P) displays since they are light, thin and have better quality. Plasma TVs have historical issues of burn-in (a condition where parts of display which gets used more often and displays worse over time). Plasma display makers are making conscious efforts to get over that problem. LCDs are equally good. However, cost for L/P televisions are fairly higher (around 2 to 3K even for a 42″ TV). Dont be caught by LCD projection TVs. Projection TVs are a completely different beast. Basically, it is about projecting a smaller picture through a lens (transmitive or reflective) onto a bigger screen. The main advantage of a projection TV is that it costs considerably less than its L/P counterparts. DLP (Digital Light Processing) is a technology from Texas Instruments which uses micro-mirrors to do image projection. It has no perceptible quality difference compared to L/P with no burn-in issues, no pixel level issues and the cost is almost 50% lesser than L/P (46″ DLP costs ~$1300). However, it is not as thin as the L/P TVs. Also, the quality is determined by the spacing between micro-mirrors in a chip, which is of the order of 1 um now. 1um is a large enough space to dilute the resolution of the TV. Not perceptible to naked eye unless you have very good eyes..:) Finally, you will have a choice between HD-ready-TV and HDTV. In the case of HD-ready, you will not have a built-in HD tuner. Its not a big deal. Most of the cable receivers, dish-network receivers have an HD tuner inside. So, you dont need it unless you want to watch things through OTA (off-the-air) antenna, though dish-network HD-receivers have an antenna input as well. You can always buy an HD tuner seperately and hook it on to your antenna output.
To sum it up, be prepared for the following questions when you buy an HDTV. Size? The bigger the better. For anything above 35″, CRT shouldnt even be considered. It is just massive and gets very heavy. Between 40″-45″, L/P and DLP all fit into the domain and it is a personal choice, given the money to performance aspect. If it is anything above 45″, projection TVs are the best option. You can choose between DLP and LCD-Projection TVs. We have a Samsung HLP5685 (56″ DLP) and it absolutely amazing. It is probably a good idea to buy the warranty for atleast 2-3 years for these TVs. I havent touched upon the different cable standards that connect the HDTVs, but then, I hope you will figure it out pretty easily when you buy these TVs. Above all, the experience of watching HD-quality cant be explained in words. It just needs to be experienced. So, go for the best !! Happy Shopping !!!