ytdl: Try to handle multi-arc videos

this currently uses a sketchy but apparently working workaround,
which will be removed once the neccessary changes in youtube-dl
are implemented

Fixes #1277

player/lua/ytdl_hook.lua

@@ -97,6 +97,28 @@ mp.add_hook("on_load", 10, function ()
         elseif not (json["_type"] == nil) and (json["_type"] == "playlist") then
             -- a playlist
 
+            -- some funky guessing to detect multi-arc videos
+            if  not (json.entries[1]["webpage_url"] == nil)
+                and (json.entries[1]["webpage_url"] == json["webpage_url"]) then
+                msg.verbose("multi-arc video detected, building EDL")
+
+
+                local playlist = "edl://"
+                for i, entry in pairs(json.entries) do
+
+                    playlist = playlist .. entry.url .. ";"
+                end
+
+                msg.debug("EDL: " .. playlist)
+
+
+                mp.set_property("stream-open-filename", playlist)
+                if not (json.title == nil) then
+                    mp.set_property("file-local-options/media-title", json.title)
+                end
+
+            else
+
                 local playlist = "#EXTM3U\n"
                 for i, entry in pairs(json.entries) do
                     local site = entry.url
@@ -114,6 +136,7 @@ mp.add_hook("on_load", 10, function ()
                 end
 
                 mp.set_property("stream-open-filename", "memory://" .. playlist)
+            end
 
         else -- probably a video
             local streamurl = ""