What is High-Def?
There are so many things out there today that claim to be High-Definition. Like the other day I saw a Windex commercial claiming that Windex would give you High-Definition glass. I was like “Are you kidding me with that!?”
I won’t be able to cover everything but I’ll try and scratch the surface and help give you a better basic understanding of HDTV.
Let’s start out with a basic definition of what High-Definition is as it pertains to Television. High-definition television (HDTV) means broadcast of television signals with a higher resolution than traditional formats. The traditional format here in the US is NTSC. (Named after the committee that created it, the National Television Systems Committee)
Now let’s cover HDTV formats. If you’ve looked at HDTV’s at your local Best Buy then I am sure you have seen the common HDTV formats of 720p and 1080i. Below I’ll list the most common formats to the US
SDTV – 480i 60 (NTSC), – This is the average Joe TV that you buy
EDTV – 480p 60, – This is what you need to use with a progressive scan DVD player
HDTV – 720p 60, 1080i 60 – the most common HDTV formats in the US
(little subscript numbers are frames per second if progressive or fields if interlaced)
An “Interlaced” signal first draws the image’s odd lines, one at a time sequentially from top to bottom (which takes 1/60 of a second), and then fills in the even lines (taking another 1/60 of a second). That is, the full picture (top to bottom) is first drawn with half its information hollowed out, and then the other half is filled in — the entire process taking 1/30 of a second.
With a “Progressive” signal the entire picture is drawn sequentially from top to bottom without the odd/even interlacing. By painting all of the scan lines sequentially from 1, 2, 3 & so on, up on one pass, we can eliminate the very slight jaggedness that comes from interlacing. Newer DVD players can output an interlaced or progressive scan image.
—–Progressive Scan—–
HDTV signals are now being broadcast in both progressive and interlaced formats: 720p (720 lines of resolution in progressive scan format) and 1080i (interlaced). So the big question is would you rather have smaller resolution with a progressive scan (720p) or a higher resolution interlaced (1080i)
The bottom line is that 1080i and 720p are both very good HDTV formats. One is not better than the other; they are just each better with particular types of subject matter. When done right, both are clearly superior to the NTSC 480-line format we have today. Also, 1080p is just right around the corner =).
Now I want to kill some HD myths
1. DVD’s are not High-Definition – DVD’s are in NTSC format, 480i or 480p depending on your DVD Player and TV, but they are not 720p or 1080i.
There are 2 DVD formats coming down the pipe which are HD-DVD and Blu-Ray. These formats will be able to give you High-Definition, but with these 2 formats get ready for a Beta vs VHS war all over again.
2. Just because a signal is 16×9 does not mean its HD and just because a signal is 4×3 does not mean it is not HD. Here is a great article on this subject, which is written by Anthony Coppedge. Very good stuff!
3. Just because you have component inputs on your TV doesn’t mean its HD and just because a piece of equipment has component outputs dosen’t mean it sends an HD signal. Your set will most likely say HDTV somewhere on it if it’s a HD set, but consult your manual if you are unsure. A component input is just another way of delivering a signal to your set.
4. Component cable will send a 720p or 1080i signal. There are better types of cable out there like DVI or HDMI which might give you a cleaner picture but component cables will get the job done.
Ok, so I think this post has gone on long enough. =) I would love to hear your comments on this post or any other HD myths that you may have heard.
Dude, I’m so with you! There’s a commercial for High Definition contacts too. Don’t even get me started about megapixels and “true HD” and other blasted forms of the sales pitch =) I would be happy to kill the “dropframe” myth too while we’re at it.
As a side note, I can’t wait for interlaced fields to become a thing of the past. There are few things more distracting (for geeks like myself) than watching a video with reversed field order. Secondly, do we really need another format war?? Can’t HD-DVD and Blu-ray just get along??!!