add directskip mode and make skip value calculation more robust

README.md

@@ -13,6 +13,9 @@ The script works best in `video-sync=audio` mode (the default in mpv), because i
 
 Sensible defaults have been set, but if you want to change the `lookahead` value take care to not set it larger than what the buffers can provide. This applies to embedded subtitles and not external.
 
+**skipmode:**
+There is an alternative speedup mode called 'skipmode'. In this mode the video doesn't speed up, but it gets skipped till the next subtitle. It can be configured to skip directly to the next subtitle or in steps. To enable skipmode set `skipmode = true` and to enable direct skip set `directskip = true`.
+
 Key Bind|Effect
 --------|------
 `ctrl + j`|Toggle script on/off

speed-transition.lua

@@ -1,7 +1,8 @@
 lookahead = 5
 speedup = 2.5
 leadin = 1 --range 0-2
-skipmode=false
+skipmode = false
+directskip = false
 ---------------
 
 normalspeed=mp.get_property_native("speed")
@@ -46,6 +47,22 @@ function check_position(_, position)
    end
 end
 
+function skipval()
+   local skipval = mp.get_property_native("demuxer-cache-duration", 5)
+   skipval = clamp(skipval, 1, 5)
+   if nextsub > 0 then
+      if nextsub-skipval-leadin <= 0 or directskip then
+         skipval = nextsub - leadin
+      end
+   else
+      skipval = clamp(skipval-leadin, 0, nil)
+      if skipval == 0 then
+         skipval = clamp(skipval-1, 1, nil)
+      end
+   end
+   return skipval
+end
+
 function speed_transition(_, sub)
    if state == 0 then
       if sub == "" then
@@ -59,11 +76,7 @@ function speed_transition(_, sub)
                temp_disable_skipmode = true
             end
             if skipmode and not temp_disable_skipmode and mp.get_property("pause") == "no" then
-               if nextsub>set_timeout()-leadin or nextsub==0 then
-                  mp.command("no-osd seek "..tostring(mp.get_property("demuxer-cache-duration")-leadin).." relative exact")
-               else
-                  mp.command("no-osd seek "..tostring(nextsub-leadin).." relative exact")
-               end
+               mp.commandv("no-osd", "seek", skipval(), "relative", "exact")
             else
                normalspeed = mp.get_property("speed")
                if mp.get_property_native("video-sync") == "audio" then