From c7f88e0ec26aea0112d3ffc58e0922f5beac4eed Mon Sep 17 00:00:00 2001
From: bitingsock <micahzech@yahoo.com>
Date: Thu, 29 Nov 2018 03:43:22 -0800
Subject: [PATCH] drop audio on desync

If avdesync > leadin then we resume too late after the subtitle should have been shown. When mpv plays with no audio, subtitles are timed to video instead of audio. This change removes audio in this case to ensure we resume on time.
---
 speed-transition.lua | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/speed-transition.lua b/speed-transition.lua
index 9a050c1..b38bd80 100644
--- a/speed-transition.lua
+++ b/speed-transition.lua
@@ -17,11 +17,13 @@ function set_timeout()
    return time_out
 end
 
+local aid
 function restore_normalspeed()
    mp.set_property("speed", normalspeed)
    if mp.get_property_native("video-sync") == "desync" then
       mp.set_property("video-sync", "audio")
    end
+   if aid~=mp.get_property("aid") then mp.set_property("aid", aid) end
 end
 
 function check_should_speedup()
@@ -36,11 +38,23 @@ function check_should_speedup()
    return nextsub, nextsub >= lookahead or nextsub == 0, mark
 end
 
+function check_audio(_,ds)
+   if state==0 then
+      return
+   end
+   if ds and tonumber(ds)>leadin then
+      aid = mp.get_property("aid")
+      mp.set_property("aid", "no")
+      print("avsync greater than leadin, dropping audio")
+   end
+end
+
 function check_position(_, position)
    if position then
       if nextsub ~= 0 and position >= (mark+nextsub-leadin) then
          restore_normalspeed()
          mp.unobserve_property(check_position)
+         mp.unobserve_property(check_audio)
       elseif nextsub == 0 and position >= (mark+set_timeout()-leadin) then
          nextsub, _ , mark = check_should_speedup()
       end
@@ -85,12 +99,15 @@ function speed_transition(_, sub)
                mp.set_property("speed", speedup)
                mp.observe_property("time-pos", "native", check_position)
                state = 1
+               aid=mp.get_property("aid")
+               mp.observe_property("avsync", "native", check_audio)
             end
          end
       end
    elseif state == 1 then
       if sub ~= "" and sub ~= nil or not mp.get_property_native("sid") then
          mp.unobserve_property(check_position)
+         mp.unobserve_property(check_audio)
          restore_normalspeed()
          state = 0
       else