[chlngr1970]

To expand on Flashs explanation a little, an Interlaced video frame is transmitted in alternating video fields. Field one is the odd scan lines, and field two is the even scan lines. Progressive scan is all 480 lines scaned in order. less flicker and better detail, but a higher bandwith since instead of 240 lines scanned in 1/30 of a second, then field two scanned in 1/30th of a sec, you have all 480 lines scanned in 1/60th of a sec. This is one reason that altough 1080i has more lines of resolution, 720p is considered better.

hope this helps.

j