There is NO SUCH THING as a Non-Square Pixel. There, I said it.

There ARE Non-square samples, and their shape IS NOT dependent on the # of scanning lines. There are also Non-Square picture elements in CCD and CMOS image sensors, but their electrical charge is never converted to digital in an analog CCTV camera.

Back in the day there actually were Non-Square pixel-based displays, but they were only used for special applications and are not found in the wild today.

If you are aware of a standard that defines the shape of 480i (NTSC) or 576i (PAL) non-square samples differently than through the use of the luminance sampling frequencies, please bring that to my attention. Thank you.