HDTV, what's with all the fuzz. A glance at SD, DVD and HD.

Note:Since TV broadcasting can vary between different areas and providers and watching still pictures is not the same as watching moving videos, this comparion is merely just to give you a rough idea of the differences between them. Also this is written by HDTV enthusiast and not professional video engineer, so everything is from personal experience only.


By now, almost everyone has heard of HDTV, hi-def tv or high-definition tv whichever way you wanna call it. Before showing screencaps of them, let me give you a rough idea of differences between different mediums. This one will only deal with SDTV (standard definition tv or the digital channels from your cable or sat.), DVD and HDTV broadcasting.

My cable provider broadcasts most of its digital channels at the resolution of 528x480. I do not have sat. but I believe they broadcast at some where around 544x480. While NTSC DVD is 720x480. HDTV can be either 1280x720 or 1920x1080. Now a tricky part is that HD channels when broadcast cannot really jump between different resolutions so they have to pick one and stick with it. As a result, when they have to show something that is not really high-definition, what they do is blow the image up to fit the resolution. This does not make the video become high-definition since you can't create details that weren't there in the first place, it is normally known as upconvert or upscale.

Then there is aspect ratios. Let's leave all others at the door and focus on 2 that mostly used with music stuffs, 4:3 (commonly known as fullscreen) and 16:9 (commonly known as widescreen). If you don't have HDTV, chances are your TV will be 4:3 (although not always true). Eventhough one can make 4:3 HD by leaving black bars on left and right of the picture, it is rarely done for the newer contents. So when they have to broadcast on both SD and HD, SD will suffer either by getting picture cropped or getting letterboxed (black bars on the top and bottom). Although letterboxed is an appropriate method the effective resolution for picture become even less. While DVD fixes this problem by providing Anamorphic feature where the whole 720x480 is used to store picture and the player or TV will then strecth it to the correct aspect ratio, SDTV broadcasting in U.S. does not really provide this feature (at least not to my knowledge). So you get a rough idea of different sizes between SD, DVD and HD, but like many things, a picture is worth a thousand words.

Click image for full size

SD letterbox from GAC

SD fullscreen from E!

DVD letterbox

DVD fullscreen

DVD widescreen anamorphic

Upconvert 4:3 in 1920x1080

Upconvert 16:9 in 1920x1080

HD 1280x720

HD 1920x1080