I think for most of broadcasting history video was fairly low quality (according to today’s standards). So I am not totally surprised that this number is low.
Yep. 1998 was when the first HD broadcasts started in the US, and it took a few years before everyone switched over. Before then, everything was 720 × 480 at 30 fps, and before the mid-80s (and for many shows for a long while after) the sound was mono, not even stereo.
Data requirements for this would be far, far lower than what is considered standard now.
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