Trailer screens in a cinema chain's lobbies

Your cinema chain has 70 cinemas. Each lobby has 6 screens that loop film trailers and ads. Today staff copy new videos onto each screen from a USB stick every Friday. Head office wants to plan every cinema's playlists centrally, since each cinema shows different films.

Each screen has a small player computer with 256 GB of storage. Videos are 1080p files of 100 to 400 MB. Head office finishes next week's playlists by Wednesday evening. Every Friday at 06:00 local time, about 15 new videos start and the ones they replace stop.

Each cinema's internet line is 50 Mbps, shared with ticket sales. It drops a few times a month, sometimes for a whole day. A screen must never go black.

How do new videos and playlists reach each screen, and what does a screen play when its cinema is offline?