MPV script that periodically saves "watch later" data during playback

autosave.lua

-- autosave.lua
--
-- Periodically saves "watch later" data during playback, rather than only saving on quit.
-- This lets you easily recover your position in the case of an ungraceful shutdown of mpv (crash, power failure, etc.).
--
-- You can configure the save period by creating a "lua-settings" directory inside your mpv configuration directory.
-- Inside the "lua-settings" directory, create a file named "autosave.conf".
-- The save period can be set like so:
--
-- save_period=60
--
-- This will set the save period to once every 60 seconds of playback, time while paused is not counted towards the save period timer.
-- The default save period is 30 seconds.

local options = require 'mp.options'

local o = {
  save_period = 30
}

options.read_options(o)

local mp = require 'mp'

local function save()
  mp.command("write-watch-later-config")
end

local function init()
  if not mp.get_property_bool("seekable", true) then
    return
  end

  local save_period_timer = mp.add_periodic_timer(o.save_period, save)

  local function pause(name, paused)
    if paused then
      save_period_timer:stop()
    else
      save_period_timer:resume()
    end
  end

  mp.observe_property("pause", "bool", pause)
end

mp.register_event("file-loaded", init)

Very nice, i wonder why this is not part of mpv

I was looking for this to make my audiobook mpv instances resilient against system crashes. As per such, a very long timer would be appropriate, since the crash is most likely to hit when the book is paused anyway.
In the current implementation however, a high save_period will lead to the saved progress lagging behind greatly.
A simple approach would be saving when pausing, but when spamming pause this spams save, which does not seem right.

What I have done is move the save_period_timer:stop() into the save function, applying it only after the first save in the paused state. When spamming pause, the timer will continuously reset and not save until the player remains in a paused or playing state for the length of save_period.

6,7c6,7
< -- You can configure the save period by creating a "lua-settings" directory inside your mpv configuration directory.
< -- Inside the "lua-settings" directory, create a file named "autosave.conf".
---
> -- You can configure the save period by creating a "script-opts" directory inside your mpv configuration directory.
> -- Inside the "script-opts" directory, create a file named "autosave.conf".
24a25,26
> local doStop = false
> local save_period_timer
26a29,33
>   
>   if doStop then
>     save_period_timer:stop()
>     doStop = false
>   end
27a35
> save_period_timer = mp.add_periodic_timer(o.save_period, save)
33,34c41
< 
<   local save_period_timer = mp.add_periodic_timer(o.save_period, save)
38c44
<       save_period_timer:stop()
---
>       doStop = true

This also uses script-opts instead of lua-settings, which has been changed 5.5 years ago with v0.29.0 by now, the old dir generates a warning in mpv