I suggest to consider raising an exception here if `settings.USE_MPLAYER and not is_loopback_connection(request)` (or returning a HttpServerErrorResponse or HttpForbidden response, as the purpose of this is on the PI, and non-"loopback" connection requests won't work.  It would be useful to tell the user about that--as the only reason to have USE_MPLAYER True at the moment is when we know non-loopback connections won't work.