>>428831
You got the numbers mixed there, it's 720x480 and 720x576 and 640x480, etc. 640/720 pixels width and 480 pixels of height ie. amount of lines (576 for PAL). But for analog broadcasts even those are just estimates, you had a few lines/pixels more or less in the active video area as a safety margin. For example the actual width is 704 pixels, with 8 added on both sides as a safety margin.
Then DVDs adopted ITU Rec.601 and once digital mastering became the norm, they tried to fill out the entire frame size as best as possible (so no more bars on the side).
>Since first widescreen LCDs were only 480 pixels high, the only way to view 4:3 content was to squish horizontally instead of stretch vertically. And that what what led people to believe 480x640 is the actual correct size of the frames