Modified VLC YouTube playlist parsing script. The original script was not working anymore because youtube removed the list_ajax interface. Unfortunately the new interface requires at least http GET method with proper headers and they are not supported by vlc. So this version makes use of an external program (youtube-dl). Disclaimer: this version…

149909-playlist_youtube.lua

--[[
 Youtube playlist importer for VLC media player 1.1 and 2.0
 Copyright 2012 Guillaume Le Maout

 Authors:  Guillaume Le Maout
 Contact: http://addons.videolan.org/messages/?action=newmessage&username=exebetche

 This program is free software; you can redistribute it and/or modify
 it under the terms of the GNU General Public License as published by
 the Free Software Foundation; either version 2 of the License, or
 (at your option) any later version.

 This program is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 GNU General Public License for more details.

 You should have received a copy of the GNU General Public License
 along with this program; if not, write to the Free Software
 Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
--]]

--[[
 MODified by Kai Gillmann, 19.01.2013, kaigillmann@googlemail.com:
 VLC HAS already a youtube importer, but not for playlists. IMO this mentioned one is
 better than this one, because it opens the video in the best possible video resolution.
 So i decided to remove all parts of the code which is not responsible for list handling.
 Now this lua script parses the list, as wanted, but for each video opened, the vlc default
 Youtube script is used, so the videos will be displayed properly.
--]]

--[[
 Youtube playlist importer for VLC media player 1.1 and 2.0
 Copyright 2012 Guillaume Le Maout

 Authors:  Guillaume Le Maout
 Contact: http://addons.videolan.org/messages/?action=newmessage&username=exebetche

 This program is free software; you can redistribute it and/or modify
 it under the terms of the GNU General Public License as published by
 the Free Software Foundation; either version 2 of the License, or
 (at your option) any later version.

 This program is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 GNU General Public License for more details.

 You should have received a copy of the GNU General Public License
 along with this program; if not, write to the Free Software
 Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
--]]

--[[
 MODified by Kai Gillmann, 19.01.2013, kaigillmann@googlemail.com:
 VLC HAS already a youtube importer, but not for playlists. IMO this mentioned one is
 better than this one, because it opens the video in the best possible video resolution.
 So i decided to remove all parts of the code which is not responsible for list handling.
 Now this lua script parses the list, as wanted, but for each video opened, the vlc default
 Youtube script is used, so the videos will be displayed properly.
--]]

--[[
 Patched by Aaron Hill (https://github.com/seraku24), 2018-05-16:
 The original script was failing in VLC 3.x due to an overzealous probe function.
 This patch makes the probe function more restrictive to avoid false positives.
--]]

--[[
 Patched by Matteo Federico Zazzetta (https://github.com/p3g4asus), 2020-02-17:
 The original script was not working anymore because youtube removed the list_ajax interface.
 Unfortunately the new interface requires at least http GET method with proper headers and 
 they are not supported by vlc. So this version makes use of an external program (youtube-dl).
 Disclaimer: this version works only under Windows. It can be easily ported but I have no way to test
 it on other OS at the moment.
 Installation (under Windows): place this file in the lua playlist vlc folder together with JSON.lua 
 (http://regex.info/code/JSON.lua) and youtube-dl.exe (https://youtube-dl.org/latest)
--]]

-- Probe function.
function probe()
     if vlc.access ~= "http" and vlc.access ~= "https" then
         return false
     end

     return string.match(vlc.path:match("([^/]+)"),"%w+.youtube.com") and (
             not string.match(vlc.path, "list_ajax") and string.match(vlc.path, "[?&]list="))
end

local function isdef(p,...)
    if not p then
        return false
    else
        local tb = p
        for i,v in ipairs(arg) do
            if tb[v]==nil then
                return false
            else
                tb = tb[v]
            end
        end
        return true
    end
end

function Log(lm)
    vlc.msg.info("[youtube_pl.lua] " .. tostring(lm))
end

function get_url_param( url, name )
    local _, _, res = string.find( url, "[&?]"..name.."=([^&]*)" )
    return res
end

function try_yt_dl(lst)
    local info = debug.getinfo(1,'S');
    local kk,jj,ll = string.match(string.sub(info.source,2), "(.-)([^\\/]-%.?([^%.\\/]*))$")
    Log("Trying ytdl "..kk)
    local link = vlc.access.."://www.youtube.com/playlist?list="..lst
    local JSON = (loadfile (kk.."JSON.lua"))()
    local bat_dir3 = "cmd /k \"\""..kk.."youtube-dl.exe\" -j --flat-playlist \""..link.."\"\""
    local f = assert(io.popen (bat_dir3, 'r'))
    local p = {}
    Log("Exec "..bat_dir3)
    -- local bat_dir2 = "> \""..kk.."youtube-dl.txt\" \""..kk.."youtube-dl.exe\" -j --flat-playlist \""..link.."\""
    -- Log("Exec "..bat_dir2)
    -- os.execute(bat_dir2)
    -- local outfile = kk.."youtube-dl.txt"
    -- Log("Open "..outfile)
    local p = {}
    for json in f:lines() do 
        Log(json)
        local rv, pall = pcall(function () return JSON:decode(json) end)
        if rv and isdef(pall,"id") then
            local item = {}
            item.path = "https://www.youtube.com/watch?v="..pall.id
            if isdef(pall,"title") then
                item.title = pall.title
            end
            if isdef(pall,"duration") then
                item.duration = math.floor(tonumber(pall.duration))
            end
            table.insert (p, item)
        end
    end
    f:close()
    return p
end

-- Parse function.
function parse()
    if string.match( vlc.path, "list=" ) then
        local lst = get_url_param(vlc.path, "list")
        return try_yt_dl(lst)
    end
end

Thanks! it solved an issue to me (no idea why or how) regarding error http 403 of mi AHK script to extract/insert URLsof playlist to VLC YouPlayTubeList

For those unable to play most videos (403 HTTP error), i have updated the youtube.lua script to use youtube-dl to get the link. Updated script