[Username1]

I believe it's less this above, and more the fact that anything taken off the camera and then sent through any kind of image processing, digital, or analog, can take the image and expand it's dynamics to the limits of the image window for transmission..... For example, while the camera may have photographed a dark scene, meant to be black, it may not show up as black unless it's tweeked a little by a video processor.... Photoshop also allows this for stills, it's called adjusting Levels.... Almost like adjusting the contrast so some of the grays are lost....

In a video, if the blacks are extended below black, they can effect sync, if white is extended beyond white, you get some noise in the sound...

Most likely anything sent over a live camera feed keeps everything out of the too black, or too white areas, Most likely the norm back in the day.... Today the black, and especially white in DVD menus are not photographed, but generated, and un naturally sent whiter than white, causing noise, blooming in that older set...