ytdl_hook: pass http proxy to ffmpeg

FFmpeg only suppports http proxies and ignores it if
the resulting url is https. Also, no SOCKS.
Use it like `--ytdl-raw-options=proxy=[http://127.0.0.1:3128]` so
it doesn't confuse mpv because of the colons.

You need to pass it as an option because youtube-dl doesn't give
us the proxy.

Or just set `http_proxy` environment variable as recommended before.

Added example using -append, which doesn't need escaping.

DOCS/man/options.rst

@@ -590,10 +590,18 @@ Program Behavior
     There is no sanity checking so it's possible to break things (i.e.
     passing invalid parameters to youtube-dl).
 
+    A proxy URL can be passed for youtube-dl to use it in parsing the website.
+    This is useful for geo-restricted URLs. After youtube-dl parsing, some
+    URLs also require a proxy for playback, so this can pass that proxy
+    information to mpv. Take note that SOCKS proxies aren't supported and
+    https URLs also bypass the proxy. This is a limitation in FFmpeg.
+
     .. admonition:: Example
 
         - ``--ytdl-raw-options=username=user,password=pass``
         - ``--ytdl-raw-options=force-ipv6=``
+        - ``--ytdl-raw-options=proxy=[http://127.0.0.1:3128]``
+        - ``--ytdl-raw-options-append=proxy=http://127.0.0.1:3128``
 
 ``--load-stats-overlay=<yes|no>``
     Enable the builtin script that shows useful playback information on a key

player/lua/ytdl_hook.lua

@@ -66,18 +66,16 @@ local function set_http_headers(http_headers)
     end
 end
 
-local function append_rtmp_prop(props, name, value)
-    if not name or not value then
-        return props
+local function append_libav_opt(props, name, value)
+    if not props then
+        props = {}
     end
 
-    if props and props ~= "" then
-        props = props..","
-    else
-        props = ""
+    if name and value and not props[name] then
+        props[name] = value
     end
 
-    return props..name.."=\""..value.."\""
+    return props
 end
 
 local function edl_escape(url)
@@ -364,23 +362,31 @@ local function add_single_video(json)
         mp.set_property('file-local-options/video-aspect', json.stretched_ratio)
     end
 
+    local stream_opts = mp.get_property_native("file-local-options/stream-lavf-o", {})
+
     -- for rtmp
     if (json.protocol == "rtmp") then
-        local rtmp_prop = append_rtmp_prop(nil,
+        stream_opts = append_libav_opt(stream_opts,
             "rtmp_tcurl", streamurl)
-        rtmp_prop = append_rtmp_prop(rtmp_prop,
+        stream_opts = append_libav_opt(stream_opts,
             "rtmp_pageurl", json.page_url)
-        rtmp_prop = append_rtmp_prop(rtmp_prop,
+        stream_opts = append_libav_opt(stream_opts,
             "rtmp_playpath", json.play_path)
-        rtmp_prop = append_rtmp_prop(rtmp_prop,
+        stream_opts = append_libav_opt(stream_opts,
             "rtmp_swfverify", json.player_url)
-        rtmp_prop = append_rtmp_prop(rtmp_prop,
+        stream_opts = append_libav_opt(stream_opts,
             "rtmp_swfurl", json.player_url)
-        rtmp_prop = append_rtmp_prop(rtmp_prop,
+        stream_opts = append_libav_opt(stream_opts,
             "rtmp_app", json.app)
-
-        mp.set_property("file-local-options/stream-lavf-o", rtmp_prop)
     end
+
+    -- ffmpeg ignores proxy if https is used and doesn't support SOCKS
+    if json.proxy and json.proxy ~= "" then
+        stream_opts = append_libav_opt(stream_opts,
+            "http_proxy", json.proxy)
+    end
+
+    mp.set_property_native("file-local-options/stream-lavf-o", stream_opts)
 end
 
 mp.add_hook(o.try_ytdl_first and "on_load" or "on_load_fail", 10, function ()
@@ -408,6 +414,7 @@ mp.add_hook(o.try_ytdl_first and "on_load" or "on_load_fail", 10, function ()
         local format = mp.get_property("options/ytdl-format")
         local raw_options = mp.get_property_native("options/ytdl-raw-options")
         local allsubs = true
+        local proxy = nil
 
         local command = {
             ytdl.path, "--no-warnings", "-J", "--flat-playlist",
@@ -437,6 +444,9 @@ mp.add_hook(o.try_ytdl_first and "on_load" or "on_load_fail", 10, function ()
             if (param == "sub-lang") and (arg ~= "") then
                 allsubs = false
             end
+            if (param == "proxy") and (arg ~= "") then
+                proxy = arg
+            end
         end
 
         if (allsubs == true) then
@@ -470,6 +480,8 @@ mp.add_hook(o.try_ytdl_first and "on_load" or "on_load_fail", 10, function ()
         msg.verbose("youtube-dl succeeded!")
         msg.debug('ytdl parsing took '..os.clock()-start_time..' seconds')
 
+        json["proxy"] = json["proxy"] or proxy
+
         -- what did we get?
         if not (json["direct"] == nil) and (json["direct"] == true) then
             -- direct URL, nothing to do