Monday morning curiousity..

Does anyone know the reason why legal range code values exist? I'm struggling to find any explaination of it, only how to correctly set up systems around it. My guess is it may have been introduced in order to store metadata in the 0-16 & 235-255 values, like the extra lines in PAL/NTSC systems.. is it even necessary anymore? is this a stupid question??

I'm dragging this up from my memory, so it may be a bit 'inaccurate, but as far as I remember it was originally for older analogue TV transmissions, to prevent over and undershoot, etc.
Such excursions caused issues with the old analogue transmission system.

It's there today mainly for backwards comparability.

Steve