diff --git a/.luacheckrc b/.luacheckrc
index 02a53f9063..7950552e3b 100644
--- a/.luacheckrc
+++ b/.luacheckrc
@@ -110,7 +110,6 @@ max_line_length = 100
 -- TODO: Remove everything below this line
 local todo = {
     "player/lua/osc.lua",
-    "player/lua/ytdl_hook.lua",
     "TOOLS/lua/ao-null-reload.lua",
     "TOOLS/lua/autocrop.lua",
     "TOOLS/lua/autodeint.lua",
diff --git a/player/lua/ytdl_hook.lua b/player/lua/ytdl_hook.lua
index 24b03e119c..7b4c9bfe66 100644
--- a/player/lua/ytdl_hook.lua
+++ b/player/lua/ytdl_hook.lua
@@ -27,14 +27,14 @@ end)
 local chapter_list = {}
 local playlist_cookies = {}
 
-function Set (t)
+local function Set (t)
     local set = {}
     for _, v in pairs(t) do set[v] = true end
     return set
 end
 
 -- ?: surrogate (keep in mind that there is no lazy evaluation)
-function iif(cond, if_true, if_false)
+local function iif(cond, if_true, if_false)
     if cond then
         return if_true
     end
@@ -766,8 +766,9 @@ local function add_single_video(json)
                     msg.verbose("adding thumbnail")
                     mp.commandv("video-add", thumb_info.url, "auto")
                     thumb_height = 0
-                elseif (thumb_preference ~= nil and (thumb_info.preference or -math.huge) > thumb_preference) or
-                    (thumb_preference == nil and ((thumb_info.height or 0) > thumb_height)) then
+                elseif (thumb_preference ~= nil and
+                        (thumb_info.preference or -math.huge) > thumb_preference) or
+                       (thumb_preference == nil and (thumb_info.height or 0) > thumb_height) then
                     thumb = thumb_info.url
                     thumb_height = thumb_info.height or 0
                     thumb_preference = thumb_info.preference
@@ -877,7 +878,7 @@ local function check_version(ytdl_path)
     end
 end
 
-function run_ytdl_hook(url)
+local function run_ytdl_hook(url)
     local start_time = os.clock()
 
     -- strip ytdl://
@@ -949,7 +950,8 @@ function run_ytdl_hook(url)
 
         for _, path in pairs(ytdl.paths_to_search) do
             -- search for youtube-dl in mpv's config dir
-            local exesuf = platform_is_windows() and not path:lower():match("%.exe$") and ".exe" or ""
+            local exesuf = platform_is_windows() and not path:lower():match("%.exe$")
+                           and ".exe" or ""
             local ytdl_cmd = mp.find_config_file(path .. exesuf)
             if ytdl_cmd then
                 msg.verbose("Found youtube-dl at: " .. ytdl_cmd)
@@ -958,11 +960,13 @@ function run_ytdl_hook(url)
                 result = exec(command)
                 break
             else
-                msg.verbose("No youtube-dl found with path " .. path .. exesuf .. " in config directories")
+                msg.verbose("No youtube-dl found with path " .. path .. exesuf ..
+                            " in config directories")
                 command[1] = path
                 result = exec(command)
                 if result.error_string == "init" then
-                    msg.verbose("youtube-dl with path " .. path .. " not found in PATH or not enough permissions")
+                    msg.verbose("youtube-dl with path " .. path ..
+                                " not found in PATH or not enough permissions")
                 else
                     msg.verbose("Found youtube-dl with path " .. path .. " in PATH")
                     ytdl.path = path
@@ -994,7 +998,7 @@ function run_ytdl_hook(url)
         msg.verbose("stderr:", result.stderr)
 
         -- trim our stderr to avoid spurious newlines
-        ytdl_err = result.stderr:gsub("^%s*(.-)%s*$", "%1")
+        local ytdl_err = result.stderr:gsub("^%s*(.-)%s*$", "%1")
         msg.error(ytdl_err)
         local err = "youtube-dl failed: "
         if result.error_string and result.error_string == "init" then