Whatever the resolution is the number that represents it is the number of horizonal lines. 720 has 720 lines that run horizonally, 1080 has 1080.

where the difference comes in is the p or the i
p= Progressive, every line is displayed on every scan
i=interlaced, odd lines are displayed on odd scans, even on even scans. Interlaced effectively takes 2 scans to display the image one time.

Depending on the power of your source input interlaced may look slightly better(yes cheaper dvd players will have a problem displaying even at 480i at times when action/movement/lots of color are on the screen).


In a wired magazine a few months back they reviewed what they called the "Rich Man's" dvd player. It was called that for a reason, cost was something like $5,000. I don't know all the detailed specs on it offhand. But it did have a built in upconverter to 1080p, component outputs, dual dvi outputs(required for the apple cinemadisplay to run at full capability, 30" lcd computer monitor, but a very nice one) and a single hdmi output. It also had 2 seperate lazers, 1 optimized for reading cds, the other optimized for reading dvds, the single lazer used in almoast every other dvd player can never read both cds and dvds as effectively as a unit that has a seperate one for each, this also improved the life of the dvd player. It was about twice the high and slightly deeper than an average dvd player, mostly for cooling purposes. It ran at full processinc power all the time. A normal dvd player will get screen jitters, or display the dark areas more of a gray when its reached its peak processing power and can't keep up with what its suposed to be displaying. Some midrange dvd players will pause for a fraction of a second while its bumps up the processinc power if the scene in a movie is too much for it to handle at its normal processing rate.

If you have everything top of the line,and have eyes good enough to see the difference, progressive will always look better than interlaced.

One way to see how fast your scan rate is on the display is something a lot of us probalby did when we were kids. Stand back about 15-20 feet from the display(or as far as your room will let you) and blow through your lips with them closed, but relaxed so you ge that sound something like a boat motor. You will visually see your display flipping with a slower scan rate(its really bad on some older pc computers). You can also get the same effect chewing on ice or something like that if theres other people around and don't want them to see you do it.

Now I don't know why this does what it does, but normally the human eye can't see a break in the picture for anything more than15-25hz(cycles per second) but for some reason you can see it even on much higher refresh like 75hz+ when you do what i described above.