time-saved.lua

local mp = require 'mp'
local msg = require 'mp.msg'

local time_saved = 0 -- TODO keep running system total

local last_time  = 0 -- FIXME reset this on on_load?
local last_speed = 1 -- FIXME not necessarily true, set this for real on on_load

local last_tick_time = 0

local function update_saved(last, new, accum, speed)
    local time_elapsed = new - last
    return accum + (time_elapsed - time_elapsed / speed)
end

mp.observe_property("speed", "number", function(name, new_speed)
    local new_time = mp.get_property_number("time-pos")
    if not new_time  then return end

    time_saved = update_saved(last_time, new_time, time_saved, last_speed)

    last_speed = new_speed
    last_time = new_time
end)


mp.add_periodic_timer(1, function()
    local new_time = mp.get_property_number("time-pos")
    if not new_time then return end
    --guard against race between timer and seek event
    if new_time > 2.0*last_speed+last_time then last_time = new_time return end

    time_saved = update_saved(last_time, new_time, time_saved, last_speed)
    last_time = new_time

    -- TODO update system total (on slower timer tho)
    msg.error("Time saved: "..time_saved)
end)

mp.register_event("seek", function()
    local new_time = mp.get_property_number("time-pos")
    if new_time < 0 then new_time = 0 end
    last_time = new_time
end)