A lesson in HD...

I was just looking at my blog, and realized I should really take down that old poll question... Then I thought "Why don't I do a post on what HD is, and some of the advantages and disadvantages thereof."  So thus the following post:

For those of you who do not know what HD is, it is most often referring to the term High Definition. What is High Definition? It simply means that the image displayed has a high number of Pixels, a term meaning very tiny individual dots of color that make up the image.
 Now, for many years the standard image size for videos was 640 x 480, meaning 640 pixels wide, by 480 pixels high.  This is known as Standard Definition. A normal DVD is almost always recorded in Standard Definition, so most of you are probably familiar with SD content. I should note here that SD content that is also Widescreen is sometimes recorded with a 720 x 480 pixel ratio, but is still considered Standard Definition...

 A quick aside on Aspect Ratio: I am sure all of my readers still remember the old TV sets and computer monitors, the ones that were about as deep as they were wide, and weighed nearly a ton... Many of you probably still own one. :-) These old screens all have a Aspect Ratio of 4:3, meaning they are 4 units of measurement wide, to 3 units of measurement high. In the case of the TVs, where they are displaying SD content, the unit of measurement is 160 pixels, which just happens to come out to 640 x 480...  In the case of the computer monitors the resolution is usually a bit higher, quite often 1280 x 1024 pixels...   
 I am sure you all have also seen a screen that is "Widescreen" -- simply meaning that the image is significantly wider than on a "Standard" screen.  Most common in HDTVs and laptop computer screens, these widescreens quite often have a pixel aspect ratio of 16:9, similarly meaning there are 16 units of width to 9 units of height.  Common resolutions in this category are 1920 x 1080,  1280 x 720, and 1440 x 900*. (*Not true 16:9, but very common in laptop screens...)

Now back to our discussion of HD video...  There are actually several different HD standards, but the most popular are 720p, and 1080i. These are simply short for 1280 x 720 Progressive, and 1920 x 1080 Interlaced.   I know I am getting more and more confusing, but stick with me...   Progressive means that the entire image that is being displayed is changed/refreshed at the same time, whereas Interlaced means that the image is changed/refreshed in two separate steps: first the odd numbered horizontal rows, then the even numbered ones.  Progressive video usually looks a little bit smoother than Interlaced video, but there really isn't much difference. Back to our main discussion... :-)

 So now that you all know what the technical terms mean, the questions remain: What does this all really mean?  Is HD really better than SD? Should I go HD? The answers aren't all that simple...  
  Basically, a HD video will look clearer or less blurry than a SD video, most of the time. It is possible for a well done SD video to actually look better than a poorly done HD video, so HD is not necessarily "Better"...  However, HD is the way of the future, and there are many inexpensive camcorders now on the market that will allow you to preserve your family memories in the clearest possible format: HD.   HD is still in it's infancy though, and unless you are willing to spend ~$100 for a BlueRay disk burner, you are stuck with keeping all of that beautiful footage on your camcorder or computer, or actually converting the video down to SD in order to put it on a standard DVD, which kind of defeats the purpose of having a HD camcorder...

 So is HD better? Maybe. Is it going to be around for a long time? Definitely. Should I make the leap and go HD? That depends on you, your tastes, and your wallet... :-) Is SD going to be around in 20 years? Probably, but much like VHS tapes, it is the way of the past.

 Hopefully that gave some of you a little bit clearer idea of what HD is, although there are probably much better explanations elsewhere, like over at Wikipedia: http://en.wikipedia.org/wiki/HD_video

  Best get to bed,
    Andrew B.