If display receives a banded image stream then it will display it which is the gist of the topics I thought. Does not matter how good the display is.
Its not that simple mate. Projectors and TV's are not like PC monitors, they all “process” the incoming video and some do a much better job than others. One display can show obvious banding while another will show non at all with the exact same input data. The display technology seems to have some influence on performance as well.
I seem to remember that all players decode what is on disc regardless and If the player truncates the video then banding could occur.
I'm not sure the decode performance of all players is equal but once decoded the player should output exactly what it decoded and thats 8bit 4:2:0. There is no need to do anything else unless the player is doing some sort of picture adjustment like brightness, contrast, colour, gamma etc.
Some players my discard below black (0-16) and above white (235-255) data but that does not affect the video range of 16-235.
Unless the player can do a better job of colour upconverting than the display its should do nothing as up converting in the player could negate better quality processing in the display or stand alone video processor and result in worse performance.
In general players should play not process.
Having a brain fart but memory says player converts 4:2:0 to 4:2:2 as a minimum and can also provide 4:4:4 or RGB colour space. I think also it converts then decides what processing it will do if any.
All modern displays convert 8bit 4:2:0 to 10bit or greater RGB for processing and display, no advantage in doing this externally if the display does this well, performance could be degraded.