>>428826 PAL DVDs are 576x720. NTSC DVDs are 480x720. Easy enough to remember. These standards were invented while CRTs were the norm, and those could screen display non-square pixels perfectly. On modern/normal square pixel monitors NTSC and PAL need to be stretched to achieve 4:3 or 16:9. 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.
VHS has horizontal resolution much LOWER than DVDs, so NTSC VHS rips can be 480x640 and that is perfectly fine.
This is all you need to know about "standard" or old resolution standards.
>>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
That didn't have to do anything with LCDs (they were still in their infancy at the time), it was due ITU Rec. 601 not having square pixels for 4:3 content. So 4:3 digital broadcasts were resized from 720x480 to 640x480 or 720x540 for viewing them on PC in the DivX era. It wasn't the "correct" resolution though, it's just the difference between source aspect ratio and display aspect ratio, but good luck explaining that to the average kid pirating Metallica and anime XVIDs.
And why use 720x540 over 640x480? It's less computationally expensive, and higher quality cause it preserves the horizontal resolution.