ytdl: add "--ytdl-params" option

This option allows the user to pass non-supported options directly to
youtube-dl, such as "--proxy URL", "--username USERNAME" and
'--password PASSWORD".

There is no sanity checking so it's possible to break things (i.e.
if you pass "--version" mpv exits with random JSON error).

Signed-off-by: wm4 <wm4@nowhere>

DOCS/man/options.rst

@@ -454,6 +454,18 @@ Program Behavior
     ``bestvideo+bestaudio``.
     (Default: ``best``)
 
+``--ytdl-raw-options=<key>=<value>[,<key>=<value>[,...]]``
+    Pass arbitraty options to youtube-dl. Parameter and argument should be
+    passed as a key-value pair. Options without argument must include ``=``.
+    
+    There is no sanity checking so it's possible to break things (i.e.
+    passing invalid parameters to youtube-dl).
+
+    .. admonition:: Example
+ 
+        ``--ytdl-raw-options=username=user,password=pass``
+        ``--ytdl-raw-options=force-ipv6=``
+
 Video
 -----
 

options/options.c

@@ -133,6 +133,7 @@ const m_option_t mp_opts[] = {
     OPT_FLAG("osc", lua_load_osc, CONF_GLOBAL),
     OPT_FLAG("ytdl", lua_load_ytdl, CONF_GLOBAL),
     OPT_STRING("ytdl-format", lua_ytdl_format, CONF_GLOBAL),
+    OPT_KEYVALUELIST("ytdl-raw-options", lua_ytdl_raw_options, CONF_GLOBAL),
     OPT_FLAG("load-scripts", auto_load_scripts, CONF_GLOBAL),
 #endif
 
@@ -716,6 +717,7 @@ const struct MPOpts mp_default_opts = {
     .lua_load_osc = 1,
     .lua_load_ytdl = 1,
     .lua_ytdl_format = NULL,
+    .lua_ytdl_raw_options = NULL,
 #endif
     .auto_load_scripts = 1,
     .loop_times = 1,

options/options.h

@@ -68,6 +68,7 @@ typedef struct MPOpts {
     int lua_load_osc;
     int lua_load_ytdl;
     char *lua_ytdl_format;
+    char **lua_ytdl_raw_options;
 
     int auto_load_scripts;
 

player/lua/ytdl_hook.lua

@@ -80,6 +80,7 @@ mp.add_hook("on_load", 10, function ()
         end
 
         local format = mp.get_property("options/ytdl-format")
+        local raw_options = mp.get_property_native("options/ytdl-raw-options")
 
         -- subformat workaround
         local subformat = "ass/srt/best"
@@ -92,6 +93,12 @@ mp.add_hook("on_load", 10, function ()
             table.insert(command, "--format")
             table.insert(command, format)
         end
+        for param, arg in pairs(raw_options) do
+            table.insert(command, "--" .. param)
+            if (arg ~= "") then
+                table.insert(command, arg)
+            end
+        end
         table.insert(command, "--")
         table.insert(command, url)
         local es, json = exec(command)