will dvd look the same on a 720 and a 1080

[edDV]

never said couldnt get 1080i, just that i carnt test it

Restate your question with detail about how you intend to display the thing whatever it is. Define that too. Is this a interlace PAL broadcast or interlace PAL DVD? Why have everyone guessing what is in your head?

[slimpickins]

ive said its pal dvd

[edDV]

An interlaced 576i PAL DVD can be directly scaled to 1080i with no other modification. Most HDTV sets can't display 1080i directly, so they will internally convert it to the native resolution of the display. A CRT set will interpolate scan lines to build up to 1080 or 1152(2x576) vertical lines but the shadow mask will only permit about 960x720 or less actual resolution to be seen.

An interlaced PAL DVD must be immediately deinterlaced for progressive displays (e.g. LCD and plasma). This can do great damage and introduce motion artifacts. Motion errors will be noticed most with sports and other high action content. The deinterlaced frames containing the deinterlacing errors are then enlarged (scaled) to the native resolution of the display.

I'll leave out DLP and projectors for now, but they have their own issues.

Native PAL has 50 fields per second or 25 frames per second which is on the edge of human flicker tolerance. Deinterlacing usually includes a process called line doubling that converts 50 fields per second to 50 frames per second to manage flicker. Movie theater projectors do much the same thing by repeating each frame twice in the gate to produce 48 fps flicker. Many still find 50Hz to have uncomfortable flicker so higher end sets repeat frames to 100Hz. 100Hz is a big marketing buzz in PAL areas. NTSC customers usually find 59.94 frames per second acceptable for flicker but there is some talk of 72 (actually 71.93) frames per second (3x23.976) in the future.

So you can see that it depends on which TV technology you buy, the native resolution of the display and the quality of the TV's image processing.

CRT and DLP sets will do best with interlace sources (excluding film sources). Most technologies work well with native progressive sources (including film) if the frame rate is adequate.