Beep when the replay buffer has fully stopped. [windows]

beep.lua

local obs = obslua
local ffi = require("ffi")

ffi.cdef[[
void Beep(int freq,int dur);
]]

function beep()
  ffi.C.Beep(7000,300)
end

function on_event(event) 
  if event == obs.OBS_FRONTEND_EVENT_REPLAY_BUFFER_STOPPED 
    then beep() 
  end 
end

function script_load(settings)
  obs.obs_frontend_add_event_callback(on_event)
end