In reply to:
I believe the image size of most broadcast material these days is 720x486 (a.k.a D1). DV is 640x480.
Woo.. welcome to my world... students, place your books under your desks.
NTSC - North America - 720x486 D1 pixel aspect - 29.97fps "drop frame"
NTSC D1 pixels are slightly taller than wide (due to the way analog TV signals have been) at a ratio of 0.9:1... jokingly refered to in the biz as "Never The Same Colour". Frame Rate of 29.97 is refered to as "drop frame" (one frame is dropped from the time code every 10 minutes to make up for the time taken in V-blank - the vertical blanking interval, the time the electron gun takes to get back to the top of the tube to redraw)
PAL - Europe - 720x576 D1 pixel aspect - 25fps
PAL D1 pixels are off square at a ratio of 1.0666:1. PAL broadcasts reverse the phase on each alternating line, which corrects for phase problems - for the most part, colour is better in a PAL transmission. Ever wonder why Mad Max looked so skinny then you saw it played here? PAL pixels are fat, NTSC pixels are thin.
DV/DVCAM/DVCPRO - 720x480 D1 pixel aspect - 29.97fps "drop frame"
I only mention this because Squirrelyz mentioned it - it's a tape format, not a broadcast format.
Having said all that... a North American TV scans 525 lines (and there are really no horizontal "pixels" as such - the gun moves discretely down every other line and is turned on and off to paint phosphors as necessary)... and European TVs scan 625 lines.
... hope this helps - I could get more indepth if anyone cares.
Oh, and Squirrelyz - if you meet the person that started that nasty rumour about "72 dpi" being broadcast dot pitch, send them my way - that's probably the one biggest problem editors run into with marketing people - "I want my logo to be 2" high, so I sent my logo 150 pixels tall"... umm... 2" tall on a 13" screen or a 65" screen?
Bren R.