Capturing video time stamps to a file in mpv

stamps.lua

require 'mp'

FNAME = "timestamps.txt"

local function file_exists(name)
   -- from https://stackoverflow.com/a/4991602
   local f=io.open(name,"r")
   if f~=nil then io.close(f) return true else return false end
end

local function dump_time_stamp()
   local exists = file_exists(FNAME)
   local f = io.open(FNAME, "a+")
   if not exists then
      f:write(
	 "Time stamps\n",
	 "00:00:00 Introduction\n"
      )
   end
   local time_pos = mp.get_property_number("time-pos")
   local time_sec = time_pos % 60
   time_pos = time_pos - time_sec
   local time_hours = math.floor(time_pos / 3600)
   time_pos = time_pos - (time_hours * 3600)
   local time_minutes = time_pos/60
   f:write(
      string.format("%02d:%02d:%02d\n", time_hours, time_minutes, time_sec)
   )
   f:close()
   mp.set_property_bool("pause", true)
end

mp.add_key_binding("Ctrl+c", "copyTime", dump_time_stamp)