High Definition (HD) ?

High Definition TV has been introduced in US since 1990s (info are available on wikipedia). So what is High Definition? HD usually contains 720 or 1080 rows from top to bottom, thus the 720p/1080p designations.The general objective for HD capable screens and videos is to provide a much finer display than SD.

Spot the differences?

In order to get the full HD experience, you must have an HD capable TV set and an HD video signal. Having an SD display would simply mean that the HD video signal would only get compressed in order to fit into the display. The reverse would also have the same result; an SD signal would only get stretched to fit an HD display. Although there are TVs that are embedded with complex algorithms that can nicely upscale an SD signal on a HD screen, which results in a better picture than on a SD screen of the same size.

Summary:
1. HD contains a lot more pixels compared to SD
2. HD creates finer images compared to SD
3. SD gets blockier much faster with larger screens than HD
4. HD video must be played in an HD display to get the HD experience
5. SD is still the most prominent format especially in TV broadcasting

Read more: Difference Between SD and HD | Difference Between | SD vs HD http://www.differencebetween.net/technology/difference-between-sd-and-hd/#ixzz11DvwslJN