ytdl: Remove DASH hacks, use DASH by default

Thanks to rcombs, ffmpeg now properly supports DASH and we can
remove our hacks for it and use it by default whenever
available. If you don't like this for whatever reason, you
can get the "normal" streams back with --ytdl-format=best .

Closes #579
Closes #1321
Closes #2359

DOCS/man/options.rst

@@ -456,16 +456,13 @@ Program Behavior
 
     If the script can't do anything with an URL, it will do nothing.
 
-    (Note: this is the replacement for the now removed libquvi support.)
-
 ``--ytdl-format=<best|worst|mp4|webm|...>``
     Video format/quality that is directly passed to youtube-dl. The possible
     values are specific to the website and the video, for a given url the
     available formats can be found with the command
     ``youtube-dl --list-formats URL``. See youtube-dl's documentation for
-    available aliases. To use experimental DASH support for youtube, use
-    ``bestvideo+bestaudio``.
-    (Default: ``best``)
+    available aliases.
+    (Default: youtube-dl's default, currently ``bestvideo+bestaudio/best``)
 
 ``--ytdl-raw-options=<key>=<value>[,<key>=<value>[,...]]``
     Pass arbitrary options to youtube-dl. Parameter and argument should be

options/options.c

@@ -717,7 +717,7 @@ const struct MPOpts mp_default_opts = {
 #if HAVE_LUA
     .lua_load_osc = 1,
     .lua_load_ytdl = 1,
-    .lua_ytdl_format = "best",
+    .lua_ytdl_format = NULL,
     .lua_ytdl_raw_options = NULL,
 #endif
     .auto_load_scripts = 1,

player/lua/ytdl_hook.lua

@@ -2,7 +2,8 @@ local utils = require 'mp.utils'
 local msg = require 'mp.msg'
 
 local ytdl = {
-    path = "youtube-dl"
+    path = "youtube-dl",
+    searched = false
 }
 
 local function exec(args)
@@ -60,6 +61,16 @@ mp.add_hook("on_load", 10, function ()
     if (url:find("http://") == 1) or (url:find("https://") == 1)
         or (url:find("ytdl://") == 1) then
 
+        -- check for youtube-dl in mpv's config dir
+        if not (ytdl.searched) then
+            local ytdl_mcd = mp.find_config_file("youtube-dl")
+            if not (ytdl_mcd == nil) then
+                msg.verbose("found youtube-dl at: " .. ytdl_mcd)
+                ytdl.path = ytdl_mcd
+            end
+            ytdl.searched = true
+        end
+
         -- strip ytdl://
         if (url:find("ytdl://") == 1) then
             url = url:sub(8)
@@ -183,19 +194,10 @@ mp.add_hook("on_load", 10, function ()
                 -- video url
                 streamurl = json["requested_formats"][1].url
 
-                if (json["ext"] == "mp4") and not (json.duration == nil) then
-                    msg.info("Using DASH, expect inaccurate duration.")
-                    msg.info("Actual duration: "..mp.format_time(json.duration))
-                end
-
                 -- audio url
                 mp.set_property("file-local-options/audio-file",
                     json["requested_formats"][2].url)
 
-                -- workaround for slow startup (causes inaccurate duration)
-                mp.set_property("file-local-options/demuxer-lavf-o",
-                    "fflags=+ignidx")
-
             elseif not (json.url == nil) then
                 -- normal video
                 streamurl = json.url