Files can be distributed over http and mpv can accept a http url as a video source.
Hence, the niketsu server could maintain a cache of a predefined maximum size and ask clients with the video source available for byte slices of this file. This file could then be served via an endpoint (password protected) which can be used by mpv directly for "streaming" from it.
Problems:
only one client can provide this file, even if multiple clients have it available, because the file could still be different (checksum)
if the providing client disconnects, requiring clients need to reload the file if another client takes over and the file is different (checksum)
Files can be distributed over http and mpv can accept a http url as a video source. Hence, the niketsu server could maintain a cache of a predefined maximum size and ask clients with the video source available for byte slices of this file. This file could then be served via an endpoint (password protected) which can be used by mpv directly for "streaming" from it.
Problems: