If you are going High Definition there are a lot of options as far as resolutions… 480p isn’t really High Definition… (See EDTV)  But there is a lot of arguments about 720p vs 1080i.  The number is the horizontal lines used in signal. 

720 is actually 1,280 lines wide, by 720 lines tall.  Compare that to 1,920 lines wide by 1,080 lines tall. 

1080 sounds like the obvious winner, and all things equal it would be.  The difference is that 720p is  a Progressive signal, which means that all of the lines are drawn in with each refresh (it starts with line one, moves to two, three, and so on.)  1080i is an interlaced signal–meaning that it only refreshes half of the lines each time (for example 1, 3, 5, 7…. then 2, 4, 6, 8)  Now all of this happens really fast, so you can’t see the difference in most cases, but in some instances… especially scenes with a lot of motion, you can start to see the interlacing.

Another factor in the progressive vs interlaced argument, is that (currently) only CRT TV’s are fast enough to show a true interlaced signal.  All of the other types (plasma, LCD, DLP etc) would show some flicker, so they have a hardware de-interlacer.  That will essentially try to guess what the missing lines would be.  There are several approaches to deinterlacing, but all of them will show a signal decrease.  Especially with a lot of motion.

A lot of people will choose the resolution based on the content.  If you want the picture to be the focus, go with 1080i.  If you are willing to sacrifice some resolution to keep action smooth, crisp and clear, choose 720p.  (If you want the best of both worlds, read my post about 1080p)

This entry was posted on Wednesday, March 21st, 2007 at 3:27 pm and is filed under Blogroll. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.