bitingsock · December 17, 2018 10:12 · Dec 17, 2018
diff --git a/speedtransition b/speedtransition
@@ -0,0 +1,216 @@
+lookahead = 5			--if the next subtitle appears after this threshold then speedup
+speedup = 5				--the value that "speed" is set to during speedup
+leadin = 1				--seconds to stop short of the next subtitle --range 0-2
+skipmode = false		--instead of speeding up playback seek to the next known subtitle
+maxskip = 5				--max seek distance (seconds) when skipmode is enabled
+directskip = false		--seek to next known subtitle no matter how far away
+dropOnAVdesync = true	--Because mpv syncs subtitles to audio it is possible that if
+						--audio processing lags behind video processing then normal playback may not resume
+						--in sync with the video. If "avsync" > leadin then this disables the audio so that
+						--we can ensure normal playback resumes on time.
+---------------
+
+normalspeed=mp.get_property_native("speed")
+
+function set_timeout()
+   local time_out
+   if mp.get_property_native("cache-size") ~= nil then
+      time_out = mp.get_property_native("cache-secs")
+   else
+      time_out = mp.get_property_native("demuxer-readahead-secs")
+   end
+   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()
+   local subdelay = mp.get_property_native("sub-delay")
+   mp.command("no-osd set sub-visibility no")
+   mp.command("no-osd sub-step 1")
+   local mark = mp.get_property_native("time-pos")
+   local nextsubdelay = mp.get_property_native("sub-delay")
+   local nextsub = subdelay - nextsubdelay
+   mp.set_property("sub-delay", subdelay)
+   mp.command("no-osd set sub-visibility yes")
+   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
+   end
+end
+
+function skipval()
+   local skipval = mp.get_property_native("demuxer-cache-duration", 5)
+   if nextsub > 0 then
+      if directskip then
+         skipval =  nextsub-leadin
+      elseif nextsub-skipval-leadin <= 0 then
+         skipval =  clamp(nextsub-leadin, 0, maxskip)
+      end
+   else
+      --skipval = clamp(skipval-leadin, 0, nil)
+      skipval = clamp(skipval-leadin, 1, nil)
+      --if skipval == 0 then
+         --skipval = clamp(skipval-1, 1, nil)
+      --end
+   end
+   print(skipval)
+   return skipval
+end
+
+function speed_transition(_, sub)
+   if state == 0 then
+      if sub == "" then
+         last_speedup_zone_begin = speedup_zone_begin
+         nextsub, shouldspeedup, speedup_zone_begin = check_should_speedup()
+         mark = speedup_zone_begin
+         speedup_zone_end = mark+nextsub
+         if shouldspeedup then
+            local temp_disable_skipmode = false
+            if last_speedup_zone_begin and mark < last_speedup_zone_begin then
+               temp_disable_skipmode = true
+            end
+            if skipmode and not temp_disable_skipmode and mp.get_property("pause") == "no" then
+               mp.commandv("no-osd", "seek", skipval(), "relative", "exact")
+            else
+               normalspeed = mp.get_property("speed")
+               if mp.get_property_native("video-sync") == "audio" then
+                  mp.set_property("video-sync", "desync")
+               end
+               mp.set_property("speed", speedup)
+               mp.observe_property("time-pos", "native", check_position)
+               state = 1
+               if dropOnAVdesync then
+                  aid=mp.get_property("aid")
+                  mp.observe_property("avsync", "native", check_audio)
+               end
+            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
+         local pos = mp.get_property_native("time-pos", 0)
+         if pos < speedup_zone_begin or pos > speedup_zone_end then
+            nextsub, _ , mark = check_should_speedup()
+         end
+      end
+   end
+end
+
+toggle2 = false
+
+function toggle_sub_visibility()
+   if not toggle2 then
+      sub_color = mp.get_property("sub-color", "1/1/1/1")
+      sub_color2 = mp.get_property("sub-border-color", "0/0/0/1")
+      sub_color3 = mp.get_property("sub-shadow-color", "0/0/0/1")
+      mp.set_property("sub-color", "0/0/0/0")
+      mp.set_property("sub-border-color", "0/0/0/0")
+      mp.set_property("sub-shadow-color", "0/0/0/0")
+   else
+      mp.set_property("sub-color", sub_color)
+      mp.set_property("sub-border-color", sub_color2)
+      mp.set_property("sub-shadow-color", sub_color3)
+   end
+   mp.osd_message("subtitle visibility: "..tostring(toggle2))
+   toggle2 = not toggle2
+end
+
+function toggle_skipmode()
+   skipmode = not skipmode
+   if enable then
+      toggle()
+      toggle()
+   end
+   if skipmode then
+      mp.osd_message("skip mode")
+   else
+      mp.osd_message("speed mode")
+   end
+end
+
+function clamp(v,l,u)
+   if l and v < l then
+      v = l
+   elseif u and v > u then
+      v = u
+   end
+   return v
+end
+
+function change_speedup(v)
+   speedup = speedup + v
+   mp.osd_message("speedup: "..speedup)
+end
+
+function change_leadin(v)
+   leadin = clamp(leadin + v, 0, 2)
+   mp.osd_message("leadin: "..leadin)
+end
+
+enable = false
+state = 0
+
+function toggle()
+   if not enable then
+      normalspeed = mp.get_property("speed")
+      mp.observe_property("sub-text", "native", speed_transition)
+      mp.osd_message("speed-transition enabled")
+   else
+      restore_normalspeed()
+      mp.unobserve_property(speed_transition)
+      mp.unobserve_property(check_position)
+      mp.osd_message("speed-transition disabled")
+   end
+   state = 0
+   enable = not enable
+end
+
+function reset_on_file_load()
+   if state == 1 then
+      mp.unobserve_property(check_position)
+      restore_normalspeed()
+      state = 0
+   end
+end
+
+mp.add_key_binding("ctrl+j", "toggle_speedtrans", toggle)
+mp.add_key_binding("alt+j", "toggle_sub_visibility", toggle_sub_visibility)
+mp.add_key_binding("ctrl+alt+j", "toggle_skipmode", toggle_skipmode)
+mp.add_key_binding("alt++", "increase_speedup", function() change_speedup(0.1) end)
+mp.add_key_binding("alt+-", "decrease_speedup", function() change_speedup(-0.1) end)
+mp.add_key_binding("alt+0", "increase_leadin", function() change_leadin(0.25) end)
+mp.add_key_binding("alt+9", "decrease_leadin", function() change_leadin(-0.25) end)
+mp.register_event("file-loaded", reset_on_file_load)