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ARTICLES - HDTV

HDTV - just what is it?

Most of us have either heard of or own HD (high Definition) TV equipment, but do you actually know what you have or even more important, don't have? Many manufacturers and sellers of HD equipment have come up with a rather confusing group of terms to help sell equipment. Read further to learn exactly what is fact and and what to look for.

There are a total of 18 approved formats for increased defination TVs, but there are only 2 formats that are true High Defination (true to the term). They are 720p and 1080i. If your new monitor or receiver does not have those specifications, you have a better resolution monitor but not HD! There are some new TV monitors out there that are advertised as EDTV .... while they do offer increased resolution over standard TV (SDTV) they can not recieve or display true HD signals.

If you pick up a sales flyer from your local electronics superstore and look at all the ads of the new HD TV monitors, you will notice that some are labeled as "HD ready" or "HD compatible". These will display a true HD signal BUT do not have the tuner to receive a HD signal. They require an external tuner (costing $500-600) to be able to watch any HD programming. Then there are some that are labeled as EDTV sets. While they provide a much better picture than a standard TV, they fall short of the resolution of true HDTV and can not display the breath-taking picture of HD. To get a HDTV set that can receive and display the true HD signal, you have to purchase a product that is labeled as "HD Built-In" If in doubt, ask the specific question as to if the product has the HD tuner built-in.

There is also another format that is called EDTV (Extended Definition TV) or 480p. EDTV is also a progressive scanned format but with less resolution of 720p. The picture quality is much better than conventional TV (SDTV) and less costly than HDTV (manufacturing costs are much less). HDTV program material has to be 'down converted' to be displayed on ED monitors, but conventional material (video tape and non-wide screen programming) looks very good on ED and is a good alternative (less expensive) to the higher cost HD monitors. A word of caution, though, as the world turns to DHTV, these monitors will become obsolete the same as SDTV sets. Basically these sets are being marketed as a stepping-stone device and look attractive to those of who are turned away by the extreme pricing of real HDTV monitors.

Ok, now that you know what is true HD, which is better? As mentioned previous, there are 2 different HD formats; 720p and 1080i. Which you you want, which is better? It may be determined for you by the type of HD monitor that you purchase. 720p (progressive scanned) monitors are usually found in flat panel units (LCD and Plasma) while 1080i (interlaced) HD is generally found in projection and tube-type monitors. So which is better? This may be a personal taste issue than a technical one. While 1080i has a higher resolution than 720p, it is not as good in rendering motion. This is a fact of the technology. the 1080i is an interlaced format like standard TV and has to present the information in two frames where the 720p format is progressive and has the capability of presenting all of the visual information at one time. Frame rates of the 720p can be 24, 30 or 60 frames/sec, but 1080i is limited to 60 frames/sec (or 50 fps if you are in PAL country). So you can see how this could be a personal choice. Most 'big screen'
movies are presented in 24 fps (as are some of the newer video cameras) and produce the "film" look that to some is more pleasing and less harsh as compared to video material. Do your own testing. Look at the two formats side-by-side with the same material and judge for yourself.

FORMAT	TOTAL LINES	ACTIVE VERTICAL LINES	ACTIVE HORIZ. LINES	VERTICAL RESOLUTION	HORIZONTAL RESOLUTION	ASPECT RATIO	FRAME RATE (fps)
SDTV(i)	525	720	480	240	330	4/3	60
SDTV(p)	525	720	480	340	330	4/3	60/30
EDTV(480p)	525	854	480	480	854	16/9	60/30/24
HDTV(720p)	768	1280	720	720	1280	16/9	60/30/24
HDTV(1080i)	1125	1920	1080	1080	1920	16/9	60 (50)
VHS				240
S-VHS/Hi-8				400
DVD/Digital Broadcast				500