# coding: utf-8

from __future__ import unicode_literals


import itertools
import json
import os.path
import random
import re
import time
import traceback

from .common import InfoExtractor, SearchInfoExtractor
from ..jsinterp import JSInterpreter
from ..swfinterp import SWFInterpreter
from ..compat import (
    compat_chr,
    compat_parse_qs,
    compat_urllib_parse_unquote,
    compat_urllib_parse_unquote_plus,
    compat_urllib_parse_urlencode,
    compat_urllib_parse_urlparse,
    compat_urlparse,
    compat_str,
)
from ..utils import (
    clean_html,
    error_to_compat_str,
    ExtractorError,
    float_or_none,
    get_element_by_attribute,
    get_element_by_id,
    int_or_none,
    mimetype2ext,
    orderedSet,
    parse_duration,
    remove_quotes,
    remove_start,
    sanitized_Request,
    smuggle_url,
    str_to_int,
    unescapeHTML,
    unified_strdate,
    unsmuggle_url,
    uppercase_escape,
    urlencode_postdata,
    ISO3166Utils,
)


class YoutubeBaseInfoExtractor(InfoExtractor):
    """Provide base functions for Youtube extractors"""
    _LOGIN_URL = 'https://accounts.google.com/ServiceLogin'
    _TWOFACTOR_URL = 'https://accounts.google.com/signin/challenge'
    _PASSWORD_CHALLENGE_URL = 'https://accounts.google.com/signin/challenge/sl/password'
    _NETRC_MACHINE = 'youtube'
    # If True it will raise an error if no login info is provided
    _LOGIN_REQUIRED = False

    def _set_language(self):
        self._set_cookie(
            '.youtube.com', 'PREF', 'f1=50000000&hl=en',
            # YouTube sets the expire time to about two months
            expire_time=time.time() + 2 * 30 * 24 * 3600)

    def _ids_to_results(self, ids):
        return [
            self.url_result(vid_id, 'Youtube', video_id=vid_id)
            for vid_id in ids]

    def _login(self):
        """
        Attempt to log in to YouTube.
        True is returned if successful or skipped.
        False is returned if login failed.

        If _LOGIN_REQUIRED is set and no authentication was provided, an error is raised.
        """
        (username, password) = self._get_login_info()
        # No authentication to be performed
        if username is None:
            if self._LOGIN_REQUIRED:
                raise ExtractorError('No login info available, needed for using %s.' % self.IE_NAME, expected=True)
            return True

        login_page = self._download_webpage(
            self._LOGIN_URL, None,
            note='Downloading login page',
            errnote='unable to fetch login page', fatal=False)
        if login_page is False:
            return

        login_form = self._hidden_inputs(login_page)

        login_form.update({
            'checkConnection': 'youtube',
            'Email': username,
            'Passwd': password,
        })

        login_results = self._download_webpage(
            self._PASSWORD_CHALLENGE_URL, None,
            note='Logging in', errnote='unable to log in', fatal=False,
            data=urlencode_postdata(login_form))
        if login_results is False:
            return False

        error_msg = self._html_search_regex(
            r'<[^>]+id="errormsg_0_Passwd"[^>]*>([^<]+)<',
            login_results, 'error message', default=None)
        if error_msg:
            raise ExtractorError('Unable to login: %s' % error_msg, expected=True)

        if re.search(r'id="errormsg_0_Passwd"', login_results) is not None:
            raise ExtractorError('Please use your account password and a two-factor code instead of an application-specific password.', expected=True)

        # Two-Factor
        # TODO add SMS and phone call support - these require making a request and then prompting the user

        if re.search(r'(?i)<form[^>]+id="challenge"', login_results) is not None:
            tfa_code = self._get_tfa_info('2-step verification code')

            if not tfa_code:
                self._downloader.report_warning(
                    'Two-factor authentication required. Provide it either interactively or with --twofactor <code>'
                    '(Note that only TOTP (Google Authenticator App) codes work at this time.)')
                return False

            tfa_code = remove_start(tfa_code, 'G-')

            tfa_form_strs = self._form_hidden_inputs('challenge', login_results)

            tfa_form_strs.update({
                'Pin': tfa_code,
                'TrustDevice': 'on',
            })

            tfa_data = urlencode_postdata(tfa_form_strs)

            tfa_req = sanitized_Request(self._TWOFACTOR_URL, tfa_data)
            tfa_results = self._download_webpage(
                tfa_req, None,
                note='Submitting TFA code', errnote='unable to submit tfa', fatal=False)

            if tfa_results is False:
                return False

            if re.search(r'(?i)<form[^>]+id="challenge"', tfa_results) is not None:
                self._downloader.report_warning('Two-factor code expired or invalid. Please try again, or use a one-use backup code instead.')
                return False
            if re.search(r'(?i)<form[^>]+id="gaia_loginform"', tfa_results) is not None:
                self._downloader.report_warning('unable to log in - did the page structure change?')
                return False
            if re.search(r'smsauth-interstitial-reviewsettings', tfa_results) is not None:
                self._downloader.report_warning('Your Google account has a security notice. Please log in on your web browser, resolve the notice, and try again.')
                return False

        if re.search(r'(?i)<form[^>]+id="gaia_loginform"', login_results) is not None:
            self._downloader.report_warning('unable to log in: bad username or password')
            return False
        return True

    def _real_initialize(self):
        if self._downloader is None:
            return
        self._set_language()
        if not self._login():
            return


class YoutubeEntryListBaseInfoExtractor(YoutubeBaseInfoExtractor):
    # Extract entries from page with "Load more" button
    def _entries(self, page, playlist_id):
        more_widget_html = content_html = page
        for page_num in itertools.count(1):
            for entry in self._process_page(content_html):
                yield entry

            mobj = re.search(r'data-uix-load-more-href="/?(?P<more>[^"]+)"', more_widget_html)
            if not mobj:
                break

            more = self._download_json(
                'https://youtube.com/%s' % mobj.group('more'), playlist_id,
                'Downloading page #%s' % page_num,
                transform_source=uppercase_escape)
            content_html = more['content_html']
            if not content_html.strip():
                # Some webpages show a "Load more" button but they don't
                # have more videos
                break
            more_widget_html = more['load_more_widget_html']


class YoutubePlaylistBaseInfoExtractor(YoutubeEntryListBaseInfoExtractor):
    def _process_page(self, content):
        for video_id, video_title in self.extract_videos_from_page(content):
            yield self.url_result(video_id, 'Youtube', video_id, video_title)

    def extract_videos_from_page(self, page):
        ids_in_page = []
        titles_in_page = []
        for mobj in re.finditer(self._VIDEO_RE, page):
            # The link with index 0 is not the first video of the playlist (not sure if still actual)
            if 'index' in mobj.groupdict() and mobj.group('id') == '0':
                continue
            video_id = mobj.group('id')
            video_title = unescapeHTML(mobj.group('title'))
            if video_title:
                video_title = video_title.strip()
            try:
                idx = ids_in_page.index(video_id)
                if video_title and not titles_in_page[idx]:
                    titles_in_page[idx] = video_title
            except ValueError:
                ids_in_page.append(video_id)
                titles_in_page.append(video_title)
        return zip(ids_in_page, titles_in_page)


class YoutubePlaylistsBaseInfoExtractor(YoutubeEntryListBaseInfoExtractor):
    def _process_page(self, content):
        for playlist_id in orderedSet(re.findall(
                r'<h3[^>]+class="[^"]*yt-lockup-title[^"]*"[^>]*><a[^>]+href="/?playlist\?list=([0-9A-Za-z-_]{10,})"',
                content)):
            yield self.url_result(
                'https://www.youtube.com/playlist?list=%s' % playlist_id, 'YoutubePlaylist')

    def _real_extract(self, url):
        playlist_id = self._match_id(url)
        webpage = self._download_webpage(url, playlist_id)
        title = self._og_search_title(webpage, fatal=False)
        return self.playlist_result(self._entries(webpage, playlist_id), playlist_id, title)


class YoutubeIE(YoutubeBaseInfoExtractor):
    IE_DESC = 'YouTube.com'
    _VALID_URL = r"""(?x)^
                     (
                         (?:https?://|//)                                    # http(s):// or protocol-independent URL
                         (?:(?:(?:(?:\w+\.)?[yY][oO][uU][tT][uU][bB][eE](?:-nocookie)?\.com/|
                            (?:www\.)?deturl\.com/www\.youtube\.com/|
                            (?:www\.)?pwnyoutube\.com/|
                            (?:www\.)?yourepeat\.com/|
                            tube\.majestyc\.net/|
                            youtube\.googleapis\.com/)                        # the various hostnames, with wildcard subdomains
                         (?:.*?\#/)?                                          # handle anchor (#/) redirect urls
                         (?:                                                  # the various things that can precede the ID:
                             (?:(?:v|embed|e)/(?!videoseries))                # v/ or embed/ or e/
                             |(?:                                             # or the v= param in all its forms
                                 (?:(?:watch|movie)(?:_popup)?(?:\.php)?/?)?  # preceding watch(_popup|.php) or nothing (like /?v=xxxx)
                                 (?:\?|\#!?)                                  # the params delimiter ? or # or #!
                                 (?:.*?[&;])??                                # any other preceding param (like /?s=tuff&v=xxxx or ?s=tuff&amp;v=V36LpHqtcDY)
                                 v=
                             )
                         ))
                         |(?:
                            youtu\.be|                                        # just youtu.be/xxxx
                            vid\.plus|                                        # or vid.plus/xxxx
                            zwearz\.com/watch|                                # or zwearz.com/watch/xxxx
                         )/
                         |(?:www\.)?cleanvideosearch\.com/media/action/yt/watch\?videoId=
                         )
                     )?                                                       # all until now is optional -> you can pass the naked ID
                     ([0-9A-Za-z_-]{11})                                      # here is it! the YouTube video ID
                     (?!.*?&list=)                                            # combined list/video URLs are handled by the playlist IE
                     (?(1).+)?                                                # if we found the ID, everything can follow
                     $"""
    _NEXT_URL_RE = r'[\?&]next_url=([^&]+)'
    _formats = {
        '5': {'ext': 'flv', 'width': 400, 'height': 240, 'acodec': 'mp3', 'abr': 64, 'vcodec': 'h263'},
        '6': {'ext': 'flv', 'width': 450, 'height': 270, 'acodec': 'mp3', 'abr': 64, 'vcodec': 'h263'},
        '13': {'ext': '3gp', 'acodec': 'aac', 'vcodec': 'mp4v'},
        '17': {'ext': '3gp', 'width': 176, 'height': 144, 'acodec': 'aac', 'abr': 24, 'vcodec': 'mp4v'},
        '18': {'ext': 'mp4', 'width': 640, 'height': 360, 'acodec': 'aac', 'abr': 96, 'vcodec': 'h264'},
        '22': {'ext': 'mp4', 'width': 1280, 'height': 720, 'acodec': 'aac', 'abr': 192, 'vcodec': 'h264'},
        '34': {'ext': 'flv', 'width': 640, 'height': 360, 'acodec': 'aac', 'abr': 128, 'vcodec': 'h264'},
        '35': {'ext': 'flv', 'width': 854, 'height': 480, 'acodec': 'aac', 'abr': 128, 'vcodec': 'h264'},
        # itag 36 videos are either 320x180 (BaW_jenozKc) or 320x240 (__2ABJjxzNo), abr varies as well
        '36': {'ext': '3gp', 'width': 320, 'acodec': 'aac', 'vcodec': 'mp4v'},
        '37': {'ext': 'mp4', 'width': 1920, 'height': 1080, 'acodec': 'aac', 'abr': 192, 'vcodec': 'h264'},
        '38': {'ext': 'mp4', 'width': 4096, 'height': 3072, 'acodec': 'aac', 'abr': 192, 'vcodec': 'h264'},
        '43': {'ext': 'webm', 'width': 640, 'height': 360, 'acodec': 'vorbis', 'abr': 128, 'vcodec': 'vp8'},
        '44': {'ext': 'webm', 'width': 854, 'height': 480, 'acodec': 'vorbis', 'abr': 128, 'vcodec': 'vp8'},
        '45': {'ext': 'webm', 'width': 1280, 'height': 720, 'acodec': 'vorbis', 'abr': 192, 'vcodec': 'vp8'},
        '46': {'ext': 'webm', 'width': 1920, 'height': 1080, 'acodec': 'vorbis', 'abr': 192, 'vcodec': 'vp8'},
        '59': {'ext': 'mp4', 'width': 854, 'height': 480, 'acodec': 'aac', 'abr': 128, 'vcodec': 'h264'},
        '78': {'ext': 'mp4', 'width': 854, 'height': 480, 'acodec': 'aac', 'abr': 128, 'vcodec': 'h264'},


        # 3D videos
        '82': {'ext': 'mp4', 'height': 360, 'format_note': '3D', 'acodec': 'aac', 'abr': 128, 'vcodec': 'h264', 'preference': -20},
        '83': {'ext': 'mp4', 'height': 480, 'format_note': '3D', 'acodec': 'aac', 'abr': 128, 'vcodec': 'h264', 'preference': -20},
        '84': {'ext': 'mp4', 'height': 720, 'format_note': '3D', 'acodec': 'aac', 'abr': 192, 'vcodec': 'h264', 'preference': -20},
        '85': {'ext': 'mp4', 'height': 1080, 'format_note': '3D', 'acodec': 'aac', 'abr': 192, 'vcodec': 'h264', 'preference': -20},
        '100': {'ext': 'webm', 'height': 360, 'format_note': '3D', 'acodec': 'vorbis', 'abr': 128, 'vcodec': 'vp8', 'preference': -20},
        '101': {'ext': 'webm', 'height': 480, 'format_note': '3D', 'acodec': 'vorbis', 'abr': 192, 'vcodec': 'vp8', 'preference': -20},
        '102': {'ext': 'webm', 'height': 720, 'format_note': '3D', 'acodec': 'vorbis', 'abr': 192, 'vcodec': 'vp8', 'preference': -20},

        # Apple HTTP Live Streaming
        '91': {'ext': 'mp4', 'height': 144, 'format_note': 'HLS', 'acodec': 'aac', 'abr': 48, 'vcodec': 'h264', 'preference': -10},
        '92': {'ext': 'mp4', 'height': 240, 'format_note': 'HLS', 'acodec': 'aac', 'abr': 48, 'vcodec': 'h264', 'preference': -10},
        '93': {'ext': 'mp4', 'height': 360, 'format_note': 'HLS', 'acodec': 'aac', 'abr': 128, 'vcodec': 'h264', 'preference': -10},
        '94': {'ext': 'mp4', 'height': 480, 'format_note': 'HLS', 'acodec': 'aac', 'abr': 128, 'vcodec': 'h264', 'preference': -10},
        '95': {'ext': 'mp4', 'height': 720, 'format_note': 'HLS', 'acodec': 'aac', 'abr': 256, 'vcodec': 'h264', 'preference': -10},
        '96': {'ext': 'mp4', 'height': 1080, 'format_note': 'HLS', 'acodec': 'aac', 'abr': 256, 'vcodec': 'h264', 'preference': -10},
        '132': {'ext': 'mp4', 'height': 240, 'format_note': 'HLS', 'acodec': 'aac', 'abr': 48, 'vcodec': 'h264', 'preference': -10},
        '151': {'ext': 'mp4', 'height': 72, 'format_note': 'HLS', 'acodec': 'aac', 'abr': 24, 'vcodec': 'h264', 'preference': -10},

        # DASH mp4 video
        '133': {'ext': 'mp4', 'height': 240, 'format_note': 'DASH video', 'vcodec': 'h264', 'preference': -40},
        '134': {'ext': 'mp4', 'height': 360, 'format_note': 'DASH video', 'vcodec': 'h264', 'preference': -40},
        '135': {'ext': 'mp4', 'height': 480, 'format_note': 'DASH video', 'vcodec': 'h264', 'preference': -40},
        '136': {'ext': 'mp4', 'height': 720, 'format_note': 'DASH video', 'vcodec': 'h264', 'preference': -40},
        '137': {'ext': 'mp4', 'height': 1080, 'format_note': 'DASH video', 'vcodec': 'h264', 'preference': -40},
        '138': {'ext': 'mp4', 'format_note': 'DASH video', 'vcodec': 'h264', 'preference': -40},  # Height can vary (https://github.com/rg3/youtube-dl/issues/4559)
        '160': {'ext': 'mp4', 'height': 144, 'format_note': 'DASH video', 'vcodec': 'h264', 'preference': -40},
        '264': {'ext': 'mp4', 'height': 1440, 'format_note': 'DASH video', 'vcodec': 'h264', 'preference': -40},
        '298': {'ext': 'mp4', 'height': 720, 'format_note': 'DASH video', 'vcodec': 'h264', 'fps': 60, 'preference': -40},
        '299': {'ext': 'mp4', 'height': 1080, 'format_note': 'DASH video', 'vcodec': 'h264', 'fps': 60, 'preference': -40},
        '266': {'ext': 'mp4', 'height': 2160, 'format_note': 'DASH video', 'vcodec': 'h264', 'preference': -40},

        # Dash mp4 audio
        '139': {'ext': 'm4a', 'format_note': 'DASH audio', 'acodec': 'aac', 'abr': 48, 'preference': -50, 'container': 'm4a_dash'},
        '140': {'ext': 'm4a', 'format_note': 'DASH audio', 'acodec': 'aac', 'abr': 128, 'preference': -50, 'container': 'm4a_dash'},
        '141': {'ext': 'm4a', 'format_note': 'DASH audio', 'acodec': 'aac', 'abr': 256, 'preference': -50, 'container': 'm4a_dash'},
        '256': {'ext': 'm4a', 'format_note': 'DASH audio', 'acodec': 'aac', 'preference': -50, 'container': 'm4a_dash'},
        '258': {'ext': 'm4a', 'format_note': 'DASH audio', 'acodec': 'aac', 'preference': -50, 'container': 'm4a_dash'},

        # Dash webm
        '167': {'ext': 'webm', 'height': 360, 'width': 640, 'format_note': 'DASH video', 'container': 'webm', 'vcodec': 'vp8', 'preference': -40},
        '168': {'ext': 'webm', 'height': 480, 'width': 854, 'format_note': 'DASH video', 'container': 'webm', 'vcodec': 'vp8', 'preference': -40},
        '169': {'ext': 'webm', 'height': 720, 'width': 1280, 'format_note': 'DASH video', 'container': 'webm', 'vcodec': 'vp8', 'preference': -40},
        '170': {'ext': 'webm', 'height': 1080, 'width': 1920, 'format_note': 'DASH video', 'container': 'webm', 'vcodec': 'vp8', 'preference': -40},
        '218': {'ext': 'webm', 'height': 480, 'width': 854, 'format_note': 'DASH video', 'container': 'webm', 'vcodec': 'vp8', 'preference': -40},
        '219': {'ext': 'webm', 'height': 480, 'width': 854, 'format_note': 'DASH video', 'container': 'webm', 'vcodec': 'vp8', 'preference': -40},
        '278': {'ext': 'webm', 'height': 144, 'format_note': 'DASH video', 'container': 'webm', 'vcodec': 'vp9', 'preference': -40},
        '242': {'ext': 'webm', 'height': 240, 'format_note': 'DASH video', 'vcodec': 'vp9', 'preference': -40},
        '243': {'ext': 'webm', 'height': 360, 'format_note': 'DASH video', 'vcodec': 'vp9', 'preference': -40},
        '244': {'ext': 'webm', 'height': 480, 'format_note': 'DASH video', 'vcodec': 'vp9', 'preference': -40},
        '245': {'ext': 'webm', 'height': 480, 'format_note': 'DASH video', 'vcodec': 'vp9', 'preference': -40},
        '246': {'ext': 'webm', 'height': 480, 'format_note': 'DASH video', 'vcodec': 'vp9', 'preference': -40},
        '247': {'ext': 'webm', 'height': 720, 'format_note': 'DASH video', 'vcodec': 'vp9', 'preference': -40},
        '248': {'ext': 'webm', 'height': 1080, 'format_note': 'DASH video', 'vcodec': 'vp9', 'preference': -40},
        '271': {'ext': 'webm', 'height': 1440, 'format_note': 'DASH video', 'vcodec': 'vp9', 'preference': -40},
        # itag 272 videos are either 3840x2160 (e.g. RtoitU2A-3E) or 7680x4320 (sLprVF6d7Ug)
        '272': {'ext': 'webm', 'height': 2160, 'format_note': 'DASH video', 'vcodec': 'vp9', 'preference': -40},
        '302': {'ext': 'webm', 'height': 720, 'format_note': 'DASH video', 'vcodec': 'vp9', 'fps': 60, 'preference': -40},
        '303': {'ext': 'webm', 'height': 1080, 'format_note': 'DASH video', 'vcodec': 'vp9', 'fps': 60, 'preference': -40},
        '308': {'ext': 'webm', 'height': 1440, 'format_note': 'DASH video', 'vcodec': 'vp9', 'fps': 60, 'preference': -40},
        '313': {'ext': 'webm', 'height': 2160, 'format_note': 'DASH video', 'vcodec': 'vp9', 'preference': -40},
        '315': {'ext': 'webm', 'height': 2160, 'format_note': 'DASH video', 'vcodec': 'vp9', 'fps': 60, 'preference': -40},

        # Dash webm audio
        '171': {'ext': 'webm', 'acodec': 'vorbis', 'format_note': 'DASH audio', 'abr': 128, 'preference': -50},
        '172': {'ext': 'webm', 'acodec': 'vorbis', 'format_note': 'DASH audio', 'abr': 256, 'preference': -50},

        # Dash webm audio with opus inside
        '249': {'ext': 'webm', 'format_note': 'DASH audio', 'acodec': 'opus', 'abr': 50, 'preference': -50},
        '250': {'ext': 'webm', 'format_note': 'DASH audio', 'acodec': 'opus', 'abr': 70, 'preference': -50},
        '251': {'ext': 'webm', 'format_note': 'DASH audio', 'acodec': 'opus', 'abr': 160, 'preference': -50},

        # RTMP (unnamed)
        '_rtmp': {'protocol': 'rtmp'},
    }
    _SUBTITLE_FORMATS = ('ttml', 'vtt')

    IE_NAME = 'youtube'
    _TESTS = [
        {
            'url': 'http://www.youtube.com/watch?v=BaW_jenozKc&t=1s&end=9',
            'info_dict': {
                'id': 'BaW_jenozKc',
                'ext': 'mp4',
                'title': 'youtube-dl test video "\'/\\ä↭𝕐',
                'uploader': 'Philipp Hagemeister',
                'uploader_id': 'phihag',
                'uploader_url': 're:https?://(?:www\.)?youtube\.com/user/phihag',
                'upload_date': '20121002',
                'license': 'Standard YouTube License',
                'description': 'test chars:  "\'/\\ä↭𝕐\ntest URL: https://github.com/rg3/youtube-dl/issues/1892\n\nThis is a test video for youtube-dl.\n\nFor more information, contact phihag@phihag.de .',
                'categories': ['Science & Technology'],
                'tags': ['youtube-dl'],
                'like_count': int,
                'dislike_count': int,
                'start_time': 1,
                'end_time': 9,
            }
        },
        {
            'url': 'http://www.youtube.com/watch?v=UxxajLWwzqY',
            'note': 'Test generic use_cipher_signature video (#897)',
            'info_dict': {
                'id': 'UxxajLWwzqY',
                'ext': 'mp4',
                'upload_date': '20120506',
                'title': 'Icona Pop - I Love It (feat. Charli XCX) [OFFICIAL VIDEO]',
                'alt_title': 'I Love It (feat. Charli XCX)',
                'description': 'md5:f3ceb5ef83a08d95b9d146f973157cc8',
                'tags': ['Icona Pop i love it', 'sweden', 'pop music', 'big beat records', 'big beat', 'charli',
                         'xcx', 'charli xcx', 'girls', 'hbo', 'i love it', "i don't care", 'icona', 'pop',
                         'iconic ep', 'iconic', 'love', 'it'],
                'uploader': 'Icona Pop',
                'uploader_id': 'IconaPop',
                'uploader_url': 're:https?://(?:www\.)?youtube\.com/user/IconaPop',
                'license': 'Standard YouTube License',
                'creator': 'Icona Pop',
            }
        },
        {
            'url': 'https://www.youtube.com/watch?v=07FYdnEawAQ',
            'note': 'Test VEVO video with age protection (#956)',
            'info_dict': {
                'id': '07FYdnEawAQ',
                'ext': 'mp4',
                'upload_date': '20130703',
                'title': 'Justin Timberlake - Tunnel Vision (Explicit)',
                'alt_title': 'Tunnel Vision',
                'description': 'md5:64249768eec3bc4276236606ea996373',
                'uploader': 'justintimberlakeVEVO',
                'uploader_id': 'justintimberlakeVEVO',
                'uploader_url': 're:https?://(?:www\.)?youtube\.com/user/justintimberlakeVEVO',
                'license': 'Standard YouTube License',
                'creator': 'Justin Timberlake',
                'age_limit': 18,
            }
        },
        {
            'url': '//www.YouTube.com/watch?v=yZIXLfi8CZQ',
            'note': 'Embed-only video (#1746)',
            'info_dict': {
                'id': 'yZIXLfi8CZQ',
                'ext': 'mp4',
                'upload_date': '20120608',
                'title': 'Principal Sexually Assaults A Teacher - Episode 117 - 8th June 2012',
                'description': 'md5:09b78bd971f1e3e289601dfba15ca4f7',
                'uploader': 'SET India',
                'uploader_id': 'setindia',
                'uploader_url': 're:https?://(?:www\.)?youtube\.com/user/setindia',
                'license': 'Standard YouTube License',
                'age_limit': 18,
            }
        },
        {
            'url': 'http://www.youtube.com/watch?v=BaW_jenozKc&v=UxxajLWwzqY',
            'note': 'Use the first video ID in the URL',
            'info_dict': {
                'id': 'BaW_jenozKc',
                'ext': 'mp4',
                'title': 'youtube-dl test video "\'/\\ä↭𝕐',
                'uploader': 'Philipp Hagemeister',
                'uploader_id': 'phihag',
                'uploader_url': 're:https?://(?:www\.)?youtube\.com/user/phihag',
                'upload_date': '20121002',
                'license': 'Standard YouTube License',
                'description': 'test chars:  "\'/\\ä↭𝕐\ntest URL: https://github.com/rg3/youtube-dl/issues/1892\n\nThis is a test video for youtube-dl.\n\nFor more information, contact phihag@phihag.de .',
                'categories': ['Science & Technology'],
                'tags': ['youtube-dl'],
                'like_count': int,
                'dislike_count': int,
            },
            'params': {
                'skip_download': True,
            },
        },
        {
            'url': 'http://www.youtube.com/watch?v=a9LDPn-MO4I',
            'note': '256k DASH audio (format 141) via DASH manifest',
            'info_dict': {
                'id': 'a9LDPn-MO4I',
                'ext': 'm4a',
                'upload_date': '20121002',
                'uploader_id': '8KVIDEO',
                'uploader_url': 're:https?://(?:www\.)?youtube\.com/user/8KVIDEO',
                'description': '',
                'uploader': '8KVIDEO',
                'license': 'Standard YouTube License',
                'title': 'UHDTV TEST 8K VIDEO.mp4'
            },
            'params': {
                'youtube_include_dash_manifest': True,
                'format': '141',
            },
            'skip': 'format 141 not served anymore',
        },
        # DASH manifest with encrypted signature
        {
            'url': 'https://www.youtube.com/watch?v=IB3lcPjvWLA',
            'info_dict': {
                'id': 'IB3lcPjvWLA',
                'ext': 'm4a',
                'title': 'Afrojack, Spree Wilson - The Spark ft. Spree Wilson',
                'description': 'md5:12e7067fa6735a77bdcbb58cb1187d2d',
                'uploader': 'AfrojackVEVO',
                'uploader_id': 'AfrojackVEVO',
                'upload_date': '20131011',
                'license': 'Standard YouTube License',
            },
            'params': {
                'youtube_include_dash_manifest': True,
                'format': '141/bestaudio[ext=m4a]',
            },
        },
        # JS player signature function name containing $
        {
            'url': 'https://www.youtube.com/watch?v=nfWlot6h_JM',
            'info_dict': {
                'id': 'nfWlot6h_JM',
                'ext': 'm4a',
                'title': 'Taylor Swift - Shake It Off',
                'alt_title': 'Shake It Off',
                'description': 'md5:95f66187cd7c8b2c13eb78e1223b63c3',
                'uploader': 'TaylorSwiftVEVO',
                'uploader_id': 'TaylorSwiftVEVO',
                'upload_date': '20140818',
                'license': 'Standard YouTube License',
                'creator': 'Taylor Swift',
            },
            'params': {
                'youtube_include_dash_manifest': True,
                'format': '141/bestaudio[ext=m4a]',
            },
        },
        # Controversy video
        {
            'url': 'https://www.youtube.com/watch?v=T4XJQO3qol8',
            'info_dict': {
                'id': 'T4XJQO3qol8',
                'ext': 'mp4',
                'upload_date': '20100909',
                'uploader': 'The Amazing Atheist',
                'uploader_id': 'TheAmazingAtheist',
                'uploader_url': 're:https?://(?:www\.)?youtube\.com/user/TheAmazingAtheist',
                'license': 'Standard YouTube License',
                'title': 'Burning Everyone\'s Koran',
                'description': 'SUBSCRIBE: http://www.youtube.com/saturninefilms\n\nEven Obama has taken a stand against freedom on this issue: http://www.huffingtonpost.com/2010/09/09/obama-gma-interview-quran_n_710282.html',
            }
        },
        # Normal age-gate video (No vevo, embed allowed)
        {
            'url': 'http://youtube.com/watch?v=HtVdAasjOgU',
            'info_dict': {
                'id': 'HtVdAasjOgU',
                'ext': 'mp4',
                'title': 'The Witcher 3: Wild Hunt - The Sword Of Destiny Trailer',
                'description': 're:(?s).{100,}About the Game\n.*?The Witcher 3: Wild Hunt.{100,}',
                'uploader': 'The Witcher',
                'uploader_id': 'WitcherGame',
                'uploader_url': 're:https?://(?:www\.)?youtube\.com/user/WitcherGame',
                'upload_date': '20140605',
                'license': 'Standard YouTube License',
                'age_limit': 18,
            },
        },
        # Age-gate video with encrypted signature
        {
            'url': 'http://www.youtube.com/watch?v=6kLq3WMV1nU',
            'info_dict': {
                'id': '6kLq3WMV1nU',
                'ext': 'mp4',
                'title': 'Dedication To My Ex (Miss That) (Lyric Video)',
                'description': 'md5:33765bb339e1b47e7e72b5490139bb41',
                'uploader': 'LloydVEVO',
                'uploader_id': 'LloydVEVO',
                'uploader_url': 're:https?://(?:www\.)?youtube\.com/user/LloydVEVO',
                'upload_date': '20110629',
                'license': 'Standard YouTube License',
                'age_limit': 18,
            },
        },
        # video_info is None (https://github.com/rg3/youtube-dl/issues/4421)
        {
            'url': '__2ABJjxzNo',
            'info_dict': {
                'id': '__2ABJjxzNo',
                'ext': 'mp4',
                'upload_date': '20100430',
                'uploader_id': 'deadmau5',
                'uploader_url': 're:https?://(?:www\.)?youtube\.com/user/deadmau5',
                'creator': 'deadmau5',
                'description': 'md5:12c56784b8032162bb936a5f76d55360',
                'uploader': 'deadmau5',
                'license': 'Standard YouTube License',
                'title': 'Deadmau5 - Some Chords (HD)',
                'alt_title': 'Some Chords',
            },
            'expected_warnings': [
                'DASH manifest missing',
            ]
        },
        # Olympics (https://github.com/rg3/youtube-dl/issues/4431)
        {
            'url': 'lqQg6PlCWgI',
            'info_dict': {
                'id': 'lqQg6PlCWgI',
                'ext': 'mp4',
                'upload_date': '20150827',
                'uploader_id': 'olympic',
                'uploader_url': 're:https?://(?:www\.)?youtube\.com/user/olympic',
                'license': 'Standard YouTube License',
                'description': 'HO09  - Women -  GER-AUS - Hockey - 31 July 2012 - London 2012 Olympic Games',
                'uploader': 'Olympic',
                'title': 'Hockey - Women -  GER-AUS - London 2012 Olympic Games',
            },
            'params': {
                'skip_download': 'requires avconv',
            }
        },
        # Non-square pixels
        {
            'url': 'https://www.youtube.com/watch?v=_b-2C3KPAM0',
            'info_dict': {
                'id': '_b-2C3KPAM0',
                'ext': 'mp4',
                'stretched_ratio': 16 / 9.,
                'upload_date': '20110310',
                'uploader_id': 'AllenMeow',
                'uploader_url': 're:https?://(?:www\.)?youtube\.com/user/AllenMeow',
                'description': 'made by Wacom from Korea | 字幕&加油添醋 by TY\'s Allen | 感謝heylisa00cavey1001同學熱情提供梗及翻譯',
                'uploader': '孫艾倫',
                'license': 'Standard YouTube License',
                'title': '[A-made] 變態妍字幕版 太妍 我就是這樣的人',
            },
        },
        # url_encoded_fmt_stream_map is empty string
        {
            'url': 'qEJwOuvDf7I',
            'info_dict': {
                'id': 'qEJwOuvDf7I',
                'ext': 'webm',
                'title': 'Обсуждение судебной практики по выборам 14 сентября 2014 года в Санкт-Петербурге',
                'description': '',
                'upload_date': '20150404',
                'uploader_id': 'spbelect',
                'uploader': 'Наблюдатели Петербурга',
            },
            'params': {
                'skip_download': 'requires avconv',
            },
            'skip': 'This live event has ended.',
        },
        # Extraction from multiple DASH manifests (https://github.com/rg3/youtube-dl/pull/6097)
        {
            'url': 'https://www.youtube.com/watch?v=FIl7x6_3R5Y',
            'info_dict': {
                'id': 'FIl7x6_3R5Y',
                'ext': 'mp4',
                'title': 'md5:7b81415841e02ecd4313668cde88737a',
                'description': 'md5:116377fd2963b81ec4ce64b542173306',
                'upload_date': '20150625',
                'uploader_id': 'dorappi2000',
                'uploader_url': 're:https?://(?:www\.)?youtube\.com/user/dorappi2000',
                'uploader': 'dorappi2000',
                'license': 'Standard YouTube License',
                'formats': 'mincount:32',
            },
        },
        # DASH manifest with segment_list
        {
            'url': 'https://www.youtube.com/embed/CsmdDsKjzN8',
            'md5': '8ce563a1d667b599d21064e982ab9e31',
            'info_dict': {
                'id': 'CsmdDsKjzN8',
                'ext': 'mp4',
                'upload_date': '20150501',  # According to '<meta itemprop="datePublished"', but in other places it's 20150510
                'uploader': 'Airtek',
                'description': 'Retransmisión en directo de la XVIII media maratón de Zaragoza.',
                'uploader_id': 'UCzTzUmjXxxacNnL8I3m4LnQ',
                'license': 'Standard YouTube License',
                'title': 'Retransmisión XVIII Media maratón Zaragoza 2015',
            },
            'params': {
                'youtube_include_dash_manifest': True,
                'format': '135',  # bestvideo
            },
            'skip': 'This live event has ended.',
        },
        {
            # Multifeed videos (multiple cameras), URL is for Main Camera
            'url': 'https://www.youtube.com/watch?v=jqWvoWXjCVs',
            'info_dict': {
                'id': 'jqWvoWXjCVs',
                'title': 'teamPGP: Rocket League Noob Stream',
                'description': 'md5:dc7872fb300e143831327f1bae3af010',
            },
            'playlist': [{
                'info_dict': {
                    'id': 'jqWvoWXjCVs',
                    'ext': 'mp4',
                    'title': 'teamPGP: Rocket League Noob Stream (Main Camera)',
                    'description': 'md5:dc7872fb300e143831327f1bae3af010',
                    'upload_date': '20150721',
                    'uploader': 'Beer Games Beer',
                    'uploader_id': 'beergamesbeer',
                    'uploader_url': 're:https?://(?:www\.)?youtube\.com/user/beergamesbeer',
                    'license': 'Standard YouTube License',
                },
            }, {
                'info_dict': {
                    'id': '6h8e8xoXJzg',
                    'ext': 'mp4',
                    'title': 'teamPGP: Rocket League Noob Stream (kreestuh)',
                    'description': 'md5:dc7872fb300e143831327f1bae3af010',
                    'upload_date': '20150721',
                    'uploader': 'Beer Games Beer',
                    'uploader_id': 'beergamesbeer',
                    'uploader_url': 're:https?://(?:www\.)?youtube\.com/user/beergamesbeer',
                    'license': 'Standard YouTube License',
                },
            }, {
                'info_dict': {
                    'id': 'PUOgX5z9xZw',
                    'ext': 'mp4',
                    'title': 'teamPGP: Rocket League Noob Stream (grizzle)',
                    'description': 'md5:dc7872fb300e143831327f1bae3af010',
                    'upload_date': '20150721',
                    'uploader': 'Beer Games Beer',
                    'uploader_id': 'beergamesbeer',
                    'uploader_url': 're:https?://(?:www\.)?youtube\.com/user/beergamesbeer',
                    'license': 'Standard YouTube License',
                },
            }, {
                'info_dict': {
                    'id': 'teuwxikvS5k',
                    'ext': 'mp4',
                    'title': 'teamPGP: Rocket League Noob Stream (zim)',
                    'description': 'md5:dc7872fb300e143831327f1bae3af010',
                    'upload_date': '20150721',
                    'uploader': 'Beer Games Beer',
                    'uploader_id': 'beergamesbeer',
                    'uploader_url': 're:https?://(?:www\.)?youtube\.com/user/beergamesbeer',
                    'license': 'Standard YouTube License',
                },
            }],
            'params': {
                'skip_download': True,
            },
        },
        {
            # Multifeed video with comma in title (see https://github.com/rg3/youtube-dl/issues/8536)
            'url': 'https://www.youtube.com/watch?v=gVfLd0zydlo',
            'info_dict': {
                'id': 'gVfLd0zydlo',
                'title': 'DevConf.cz 2016 Day 2 Workshops 1 14:00 - 15:30',
            },
            'playlist_count': 2,
            'skip': 'Not multifeed anymore',
        },
        {
            'url': 'http://vid.plus/FlRa-iH7PGw',
            'only_matching': True,
        },
        {
            'url': 'http://zwearz.com/watch/9lWxNJF-ufM/electra-woman-dyna-girl-official-trailer-grace-helbig.html',
            'only_matching': True,
        },
        {
            # Title with JS-like syntax "};" (see https://github.com/rg3/youtube-dl/issues/7468)
            # Also tests cut-off URL expansion in video description (see
            # https://github.com/rg3/youtube-dl/issues/1892,
            # https://github.com/rg3/youtube-dl/issues/8164)
            'url': 'https://www.youtube.com/watch?v=lsguqyKfVQg',
            'info_dict': {
                'id': 'lsguqyKfVQg',
                'ext': 'mp4',
                'title': '{dark walk}; Loki/AC/Dishonored; collab w/Elflover21',
                'alt_title': 'Dark Walk',
                'description': 'md5:8085699c11dc3f597ce0410b0dcbb34a',
                'upload_date': '20151119',
                'uploader_id': 'IronSoulElf',
                'uploader_url': 're:https?://(?:www\.)?youtube\.com/user/IronSoulElf',
                'uploader': 'IronSoulElf',
                'license': 'Standard YouTube License',
                'creator': 'Todd Haberman, Daniel Law Heath & Aaron Kaplan',
            },
            'params': {
                'skip_download': True,
            },
        },
        {
            # Tags with '};' (see https://github.com/rg3/youtube-dl/issues/7468)
            'url': 'https://www.youtube.com/watch?v=Ms7iBXnlUO8',
            'only_matching': True,
        },
        {
            # Video with yt:stretch=17:0
            'url': 'https://www.youtube.com/watch?v=Q39EVAstoRM',
            'info_dict': {
                'id': 'Q39EVAstoRM',
                'ext': 'mp4',
                'title': 'Clash Of Clans#14 Dicas De Ataque Para CV 4',
                'description': 'md5:ee18a25c350637c8faff806845bddee9',
                'upload_date': '20151107',
                'uploader_id': 'UCCr7TALkRbo3EtFzETQF1LA',
                'uploader': 'CH GAMER DROID',
            },
            'params': {
                'skip_download': True,
            },
            'skip': 'This video does not exist.',
        },
        {
            # Video licensed under Creative Commons
            'url': 'https://www.youtube.com/watch?v=M4gD1WSo5mA',
            'info_dict': {
                'id': 'M4gD1WSo5mA',
                'ext': 'mp4',
                'title': 'md5:e41008789470fc2533a3252216f1c1d1',
                'description': 'md5:a677553cf0840649b731a3024aeff4cc',
                'upload_date': '20150127',
                'uploader_id': 'BerkmanCenter',
                'uploader_url': 're:https?://(?:www\.)?youtube\.com/user/BerkmanCenter',
                'uploader': 'BerkmanCenter',
                'license': 'Creative Commons Attribution license (reuse allowed)',
            },
            'params': {
                'skip_download': True,
            },
        },
        {
            # Channel-like uploader_url
            'url': 'https://www.youtube.com/watch?v=eQcmzGIKrzg',
            'info_dict': {
                'id': 'eQcmzGIKrzg',
                'ext': 'mp4',
                'title': 'Democratic Socialism and Foreign Policy | Bernie Sanders',
                'description': 'md5:dda0d780d5a6e120758d1711d062a867',
                'upload_date': '20151119',
                'uploader': 'Bernie 2016',
                'uploader_id': 'UCH1dpzjCEiGAt8CXkryhkZg',
                'uploader_url': 're:https?://(?:www\.)?youtube\.com/channel/UCH1dpzjCEiGAt8CXkryhkZg',
                'license': 'Creative Commons Attribution license (reuse allowed)',
            },
            'params': {
                'skip_download': True,
            },
        },
        {
            'url': 'https://www.youtube.com/watch?feature=player_embedded&amp;amp;v=V36LpHqtcDY',
            'only_matching': True,
        },
        {
            # YouTube Red paid video (https://github.com/rg3/youtube-dl/issues/10059)
            'url': 'https://www.youtube.com/watch?v=i1Ko8UG-Tdo',
            'only_matching': True,
        }
    ]

    def __init__(self, *args, **kwargs):
        super(YoutubeIE, self).__init__(*args, **kwargs)
        self._player_cache = {}

    def report_video_info_webpage_download(self, video_id):
        """Report attempt to download video info webpage."""
        self.to_screen('%s: Downloading video info webpage' % video_id)

    def report_information_extraction(self, video_id):
        """Report attempt to extract video information."""
        self.to_screen('%s: Extracting video information' % video_id)

    def report_unavailable_format(self, video_id, format):
        """Report extracted video URL."""
        self.to_screen('%s: Format %s not available' % (video_id, format))

    def report_rtmp_download(self):
        """Indicate the download will use the RTMP protocol."""
        self.to_screen('RTMP download detected')

    def _signature_cache_id(self, example_sig):
        """ Return a string representation of a signature """
        return '.'.join(compat_str(len(part)) for part in example_sig.split('.'))

    def _extract_signature_function(self, video_id, player_url, example_sig):
        id_m = re.match(
            r'.*?-(?P<id>[a-zA-Z0-9_-]+)(?:/watch_as3|/html5player(?:-new)?|/base)?\.(?P<ext>[a-z]+)$',
            player_url)
        if not id_m:
            raise ExtractorError('Cannot identify player %r' % player_url)
        player_type = id_m.group('ext')
        player_id = id_m.group('id')

        # Read from filesystem cache
        func_id = '%s_%s_%s' % (
            player_type, player_id, self._signature_cache_id(example_sig))
        assert os.path.basename(func_id) == func_id

        cache_spec = self._downloader.cache.load('youtube-sigfuncs', func_id)
        if cache_spec is not None:
            return lambda s: ''.join(s[i] for i in cache_spec)

        download_note = (
            'Downloading player %s' % player_url
            if self._downloader.params.get('verbose') else
            'Downloading %s player %s' % (player_type, player_id)
        )
        if player_type == 'js':
            code = self._download_webpage(
                player_url, video_id,
                note=download_note,
                errnote='Download of %s failed' % player_url)
            res = self._parse_sig_js(code)
        elif player_type == 'swf':
            urlh = self._request_webpage(
                player_url, video_id,
                note=download_note,
                errnote='Download of %s failed' % player_url)
            code = urlh.read()
            res = self._parse_sig_swf(code)
        else:
            assert False, 'Invalid player type %r' % player_type

        test_string = ''.join(map(compat_chr, range(len(example_sig))))
        cache_res = res(test_string)
        cache_spec = [ord(c) for c in cache_res]

        self._downloader.cache.store('youtube-sigfuncs', func_id, cache_spec)
        return res

    def _print_sig_code(self, func, example_sig):
        def gen_sig_code(idxs):
            def _genslice(start, end, step):
                starts = '' if start == 0 else str(start)
                ends = (':%d' % (end + step)) if end + step >= 0 else ':'
                steps = '' if step == 1 else (':%d' % step)
                return 's[%s%s%s]' % (starts, ends, steps)

            step = None
            # Quelch pyflakes warnings - start will be set when step is set
            start = '(Never used)'
            for i, prev in zip(idxs[1:], idxs[:-1]):
                if step is not None:
                    if i - prev == step:
                        continue
                    yield _genslice(start, prev, step)
                    step = None
                    continue
                if i - prev in [-1, 1]:
                    step = i - prev
                    start = prev
                    continue
                else:
                    yield 's[%d]' % prev
            if step is None:
                yield 's[%d]' % i
            else:
                yield _genslice(start, i, step)

        test_string = ''.join(map(compat_chr, range(len(example_sig))))
        cache_res = func(test_string)
        cache_spec = [ord(c) for c in cache_res]
        expr_code = ' + '.join(gen_sig_code(cache_spec))
        signature_id_tuple = '(%s)' % (
            ', '.join(compat_str(len(p)) for p in example_sig.split('.')))
        code = ('if tuple(len(p) for p in s.split(\'.\')) == %s:\n'
                '    return %s\n') % (signature_id_tuple, expr_code)
        self.to_screen('Extracted signature function:\n' + code)

    def _parse_sig_js(self, jscode):
        funcname = self._search_regex(
            r'\.sig\|\|([a-zA-Z0-9$]+)\(', jscode,
            'Initial JS player signature function name')

        jsi = JSInterpreter(jscode)
        initial_function = jsi.extract_function(funcname)
        return lambda s: initial_function([s])

    def _parse_sig_swf(self, file_contents):
        swfi = SWFInterpreter(file_contents)
        TARGET_CLASSNAME = 'SignatureDecipher'
        searched_class = swfi.extract_class(TARGET_CLASSNAME)
        initial_function = swfi.extract_function(searched_class, 'decipher')
        return lambda s: initial_function([s])

    def _decrypt_signature(self, s, video_id, player_url, age_gate=False):
        """Turn the encrypted s field into a working signature"""

        if player_url is None:
            raise ExtractorError('Cannot decrypt signature without player_url')

        if player_url.startswith('//'):
            player_url = 'https:' + player_url
        try:
            player_id = (player_url, self._signature_cache_id(s))
            if player_id not in self._player_cache:
                func = self._extract_signature_function(
                    video_id, player_url, s
                )
                self._player_cache[player_id] = func
            func = self._player_cache[player_id]
            if self._downloader.params.get('youtube_print_sig_code'):
                self._print_sig_code(func, s)
            return func(s)
        except Exception as e:
            tb = traceback.format_exc()
            raise ExtractorError(
                'Signature extraction failed: ' + tb, cause=e)

    def _get_subtitles(self, video_id, webpage):
        try:
            subs_doc = self._download_xml(
                'https://video.google.com/timedtext?hl=en&type=list&v=%s' % video_id,
                video_id, note=False)
        except ExtractorError as err:
            self._downloader.report_warning('unable to download video subtitles: %s' % error_to_compat_str(err))
            return {}

        sub_lang_list = {}
        for track in subs_doc.findall('track'):
            lang = track.attrib['lang_code']
            if lang in sub_lang_list:
                continue
            sub_formats = []
            for ext in self._SUBTITLE_FORMATS:
                params = compat_urllib_parse_urlencode({
                    'lang': lang,
                    'v': video_id,
                    'fmt': ext,
                    'name': track.attrib['name'].encode('utf-8'),
                })
                sub_formats.append({
                    'url': 'https://www.youtube.com/api/timedtext?' + params,
                    'ext': ext,
                })
            sub_lang_list[lang] = sub_formats
        if not sub_lang_list:
            self._downloader.report_warning('video doesn\'t have subtitles')
            return {}
        return sub_lang_list

    def _get_ytplayer_config(self, video_id, webpage):
        patterns = (
            # User data may contain arbitrary character sequences that may affect
            # JSON extraction with regex, e.g. when '};' is contained the second
            # regex won't capture the whole JSON. Yet working around by trying more
            # concrete regex first keeping in mind proper quoted string handling
            # to be implemented in future that will replace this workaround (see
            # https://github.com/rg3/youtube-dl/issues/7468,
            # https://github.com/rg3/youtube-dl/pull/7599)
            r';ytplayer\.config\s*=\s*({.+?});ytplayer',
            r';ytplayer\.config\s*=\s*({.+?});',
        )
        config = self._search_regex(
            patterns, webpage, 'ytplayer.config', default=None)
        if config:
            return self._parse_json(
                uppercase_escape(config), video_id, fatal=False)

    def _get_automatic_captions(self, video_id, webpage):
        """We need the webpage for getting the captions url, pass it as an
           argument to speed up the process."""
        self.to_screen('%s: Looking for automatic captions' % video_id)
        player_config = self._get_ytplayer_config(video_id, webpage)
        err_msg = 'Couldn\'t find automatic captions for %s' % video_id
        if not player_config:
            self._downloader.report_warning(err_msg)
            return {}
        try:
            args = player_config['args']
            caption_url = args.get('ttsurl')
            if caption_url:
                timestamp = args['timestamp']
                # We get the available subtitles
                list_params = compat_urllib_parse_urlencode({
                    'type': 'list',
                    'tlangs': 1,
                    'asrs': 1,
                })
                list_url = caption_url + '&' + list_params
                caption_list = self._download_xml(list_url, video_id)
                original_lang_node = caption_list.find('track')
                if original_lang_node is None:
                    self._downloader.report_warning('Video doesn\'t have automatic captions')
                    return {}
                original_lang = original_lang_node.attrib['lang_code']
                caption_kind = original_lang_node.attrib.get('kind', '')

                sub_lang_list = {}
                for lang_node in caption_list.findall('target'):
                    sub_lang = lang_node.attrib['lang_code']
                    sub_formats = []
                    for ext in self._SUBTITLE_FORMATS:
                        params = compat_urllib_parse_urlencode({
                            'lang': original_lang,
                            'tlang': sub_lang,
                            'fmt': ext,
                            'ts': timestamp,
                            'kind': caption_kind,
                        })
                        sub_formats.append({
                            'url': caption_url + '&' + params,
                            'ext': ext,
                        })
                    sub_lang_list[sub_lang] = sub_formats
                return sub_lang_list

            # Some videos don't provide ttsurl but rather caption_tracks and
            # caption_translation_languages (e.g. 20LmZk1hakA)
            caption_tracks = args['caption_tracks']
            caption_translation_languages = args['caption_translation_languages']
            caption_url = compat_parse_qs(caption_tracks.split(',')[0])['u'][0]
            parsed_caption_url = compat_urllib_parse_urlparse(caption_url)
            caption_qs = compat_parse_qs(parsed_caption_url.query)

            sub_lang_list = {}
            for lang in caption_translation_languages.split(','):
                lang_qs = compat_parse_qs(compat_urllib_parse_unquote_plus(lang))
                sub_lang = lang_qs.get('lc', [None])[0]
                if not sub_lang:
                    continue
                sub_formats = []
                for ext in self._SUBTITLE_FORMATS:
                    caption_qs.update({
                        'tlang': [sub_lang],
                        'fmt': [ext],
                    })
                    sub_url = compat_urlparse.urlunparse(parsed_caption_url._replace(
                        query=compat_urllib_parse_urlencode(caption_qs, True)))
                    sub_formats.append({
                        'url': sub_url,
                        'ext': ext,
                    })
                sub_lang_list[sub_lang] = sub_formats
            return sub_lang_list
        # An extractor error can be raise by the download process if there are
        # no automatic captions but there are subtitles
        except (KeyError, ExtractorError):
            self._downloader.report_warning(err_msg)
            return {}

    def _mark_watched(self, video_id, video_info):
        playback_url = video_info.get('videostats_playback_base_url', [None])[0]
        if not playback_url:
            return
        parsed_playback_url = compat_urlparse.urlparse(playback_url)
        qs = compat_urlparse.parse_qs(parsed_playback_url.query)

        # cpn generation algorithm is reverse engineered from base.js.
        # In fact it works even with dummy cpn.
        CPN_ALPHABET = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789-_'
        cpn = ''.join((CPN_ALPHABET[random.randint(0, 256) & 63] for _ in range(0, 16)))

        qs.update({
            'ver': ['2'],
            'cpn': [cpn],
        })
        playback_url = compat_urlparse.urlunparse(
            parsed_playback_url._replace(query=compat_urllib_parse_urlencode(qs, True)))

        self._download_webpage(
            playback_url, video_id, 'Marking watched',
            'Unable to mark watched', fatal=False)

    @classmethod
    def extract_id(cls, url):
        mobj = re.match(cls._VALID_URL, url, re.VERBOSE)
        if mobj is None:
            raise ExtractorError('Invalid URL: %s' % url)
        video_id = mobj.group(2)
        return video_id

    def _extract_from_m3u8(self, manifest_url, video_id):
        url_map = {}

        def _get_urls(_manifest):
            lines = _manifest.split('\n')
            urls = filter(lambda l: l and not l.startswith('#'),
                          lines)
            return urls
        manifest = self._download_webpage(manifest_url, video_id, 'Downloading formats manifest')
        formats_urls = _get_urls(manifest)
        for format_url in formats_urls:
            itag = self._search_regex(r'itag/(\d+?)/', format_url, 'itag')
            url_map[itag] = format_url
        return url_map

    def _extract_annotations(self, video_id):
        url = 'https://www.youtube.com/annotations_invideo?features=1&legacy=1&video_id=%s' % video_id
        return self._download_webpage(url, video_id, note='Searching for annotations.', errnote='Unable to download video annotations.')

    def _real_extract(self, url):
        url, smuggled_data = unsmuggle_url(url, {})

        proto = (
            'http' if self._downloader.params.get('prefer_insecure', False)
            else 'https')

        start_time = None
        end_time = None
        parsed_url = compat_urllib_parse_urlparse(url)
        for component in [parsed_url.fragment, parsed_url.query]:
            query = compat_parse_qs(component)
            if start_time is None and 't' in query:
                start_time = parse_duration(query['t'][0])
            if start_time is None and 'start' in query:
                start_time = parse_duration(query['start'][0])
            if end_time is None and 'end' in query:
                end_time = parse_duration(query['end'][0])

        # Extract original video URL from URL with redirection, like age verification, using next_url parameter
        mobj = re.search(self._NEXT_URL_RE, url)
        if mobj:
            url = proto + '://www.youtube.com/' + compat_urllib_parse_unquote(mobj.group(1)).lstrip('/')
        video_id = self.extract_id(url)

        # Get video webpage
        url = proto + '://www.youtube.com/watch?v=%s&gl=US&hl=en&has_verified=1&bpctr=9999999999' % video_id
        video_webpage = self._download_webpage(url, video_id)

        # Attempt to extract SWF player URL
        mobj = re.search(r'swfConfig.*?"(https?:\\/\\/.*?watch.*?-.*?\.swf)"', video_webpage)
        if mobj is not None:
            player_url = re.sub(r'\\(.)', r'\1', mobj.group(1))
        else:
            player_url = None

        dash_mpds = []

        def add_dash_mpd(video_info):
            dash_mpd = video_info.get('dashmpd')
            if dash_mpd and dash_mpd[0] not in dash_mpds:
                dash_mpds.append(dash_mpd[0])

        # Get video info
        embed_webpage = None
        is_live = None
        if re.search(r'player-age-gate-content">', video_webpage) is not None:
            age_gate = True
            # We simulate the access to the video from www.youtube.com/v/{video_id}
            # this can be viewed without login into Youtube
            url = proto + '://www.youtube.com/embed/%s' % video_id
            embed_webpage = self._download_webpage(url, video_id, 'Downloading embed webpage')
            data = compat_urllib_parse_urlencode({
                'video_id': video_id,
                'eurl': 'https://youtube.googleapis.com/v/' + video_id,
                'sts': self._search_regex(
                    r'"sts"\s*:\s*(\d+)', embed_webpage, 'sts', default=''),
            })
            video_info_url = proto + '://www.youtube.com/get_video_info?' + data
            video_info_webpage = self._download_webpage(
                video_info_url, video_id,
                note='Refetching age-gated info webpage',
                errnote='unable to download video info webpage')
            video_info = compat_parse_qs(video_info_webpage)
            add_dash_mpd(video_info)
        else:
            age_gate = False
            video_info = None
            # Try looking directly into the video webpage
            ytplayer_config = self._get_ytplayer_config(video_id, video_webpage)
            if ytplayer_config:
                args = ytplayer_config['args']
                if args.get('url_encoded_fmt_stream_map'):
                    # Convert to the same format returned by compat_parse_qs
                    video_info = dict((k, [v]) for k, v in args.items())
                    add_dash_mpd(video_info)
                if args.get('livestream') == '1' or args.get('live_playback') == 1:
                    is_live = True
            if not video_info or self._downloader.params.get('youtube_include_dash_manifest', True):
                # We also try looking in get_video_info since it may contain different dashmpd
                # URL that points to a DASH manifest with possibly different itag set (some itags
                # are missing from DASH manifest pointed by webpage's dashmpd, some - from DASH
                # manifest pointed by get_video_info's dashmpd).
                # The general idea is to take a union of itags of both DASH manifests (for example
                # video with such 'manifest behavior' see https://github.com/rg3/youtube-dl/issues/6093)
                self.report_video_info_webpage_download(video_id)
                for el_type in ['&el=info', '&el=embedded', '&el=detailpage', '&el=vevo', '']:
                    video_info_url = (
                        '%s://www.youtube.com/get_video_info?&video_id=%s%s&ps=default&eurl=&gl=US&hl=en'
                        % (proto, video_id, el_type))
                    video_info_webpage = self._download_webpage(
                        video_info_url,
                        video_id, note=False,
                        errnote='unable to download video info webpage')
                    get_video_info = compat_parse_qs(video_info_webpage)
                    if get_video_info.get('use_cipher_signature') != ['True']:
                        add_dash_mpd(get_video_info)
                    if not video_info:
                        video_info = get_video_info
                    if 'token' in get_video_info:
                        # Different get_video_info requests may report different results, e.g.
                        # some may report video unavailability, but some may serve it without
                        # any complaint (see https://github.com/rg3/youtube-dl/issues/7362,
                        # the original webpage as well as el=info and el=embedded get_video_info
                        # requests report video unavailability due to geo restriction while
                        # el=detailpage succeeds and returns valid data). This is probably
                        # due to YouTube measures against IP ranges of hosting providers.
                        # Working around by preferring the first succeeded video_info containing
                        # the token if no such video_info yet was found.
                        if 'token' not in video_info:
                            video_info = get_video_info
                        break
        if 'token' not in video_info:
            if 'reason' in video_info:
                if 'The uploader has not made this video available in your country.' in video_info['reason']:
                    regions_allowed = self._html_search_meta('regionsAllowed', video_webpage, default=None)
                    if regions_allowed:
                        raise ExtractorError('YouTube said: This video is available in %s only' % (
                            ', '.join(map(ISO3166Utils.short2full, regions_allowed.split(',')))),
                            expected=True)
                raise ExtractorError(
                    'YouTube said: %s' % video_info['reason'][0],
                    expected=True, video_id=video_id)
            else:
                raise ExtractorError(
                    '"token" parameter not in video info for unknown reason',
                    video_id=video_id)

        # title
        if 'title' in video_info:
            video_title = video_info['title'][0]
        else:
            self._downloader.report_warning('Unable to extract video title')
            video_title = '_'

        # description
        video_description = get_element_by_id("eow-description", video_webpage)
        if video_description:
            video_description = re.sub(r'''(?x)
                <a\s+
                    (?:[a-zA-Z-]+="[^"]*"\s+)*?
                    (?:title|href)="([^"]+)"\s+
                    (?:[a-zA-Z-]+="[^"]*"\s+)*?
                    class="[^"]*"[^>]*>
                [^<]+\.{3}\s*
                </a>
            ''', r'\1', video_description)
            video_description = clean_html(video_description)
        else:
            fd_mobj = re.search(r'<meta name="description" content="([^"]+)"', video_webpage)
            if fd_mobj:
                video_description = unescapeHTML(fd_mobj.group(1))
            else:
                video_description = ''

        if 'multifeed_metadata_list' in video_info and not smuggled_data.get('force_singlefeed', False):
            if not self._downloader.params.get('noplaylist'):
                entries = []
                feed_ids = []
                multifeed_metadata_list = video_info['multifeed_metadata_list'][0]
                for feed in multifeed_metadata_list.split(','):
                    # Unquote should take place before split on comma (,) since textual
                    # fields may contain comma as well (see
                    # https://github.com/rg3/youtube-dl/issues/8536)
                    feed_data = compat_parse_qs(compat_urllib_parse_unquote_plus(feed))
                    entries.append({
                        '_type': 'url_transparent',
                        'ie_key': 'Youtube',
                        'url': smuggle_url(
                            '%s://www.youtube.com/watch?v=%s' % (proto, feed_data['id'][0]),
                            {'force_singlefeed': True}),
                        'title': '%s (%s)' % (video_title, feed_data['title'][0]),
                    })
                    feed_ids.append(feed_data['id'][0])
                self.to_screen(
                    'Downloading multifeed video (%s) - add --no-playlist to just download video %s'
                    % (', '.join(feed_ids), video_id))
                return self.playlist_result(entries, video_id, video_title, video_description)
            self.to_screen('Downloading just video %s because of --no-playlist' % video_id)

        if 'view_count' in video_info:
            view_count = int(video_info['view_count'][0])
        else:
            view_count = None

        # Check for "rental" videos
        if 'ypc_video_rental_bar_text' in video_info and 'author' not in video_info:
            raise ExtractorError('"rental" videos not supported')

        # Start extracting information
        self.report_information_extraction(video_id)

        # uploader
        if 'author' not in video_info:
            raise ExtractorError('Unable to extract uploader name')
        video_uploader = compat_urllib_parse_unquote_plus(video_info['author'][0])

        # uploader_id
        video_uploader_id = None
        video_uploader_url = None
        mobj = re.search(
            r'<link itemprop="url" href="(?P<uploader_url>https?://www.youtube.com/(?:user|channel)/(?P<uploader_id>[^"]+))">',
            video_webpage)
        if mobj is not None:
            video_uploader_id = mobj.group('uploader_id')
            video_uploader_url = mobj.group('uploader_url')
        else:
            self._downloader.report_warning('unable to extract uploader nickname')

        # thumbnail image
        # We try first to get a high quality image:
        m_thumb = re.search(r'<span itemprop="thumbnail".*?href="(.*?)">',
                            video_webpage, re.DOTALL)
        if m_thumb is not None:
            video_thumbnail = m_thumb.group(1)
        elif 'thumbnail_url' not in video_info:
            self._downloader.report_warning('unable to extract video thumbnail')
            video_thumbnail = None
        else:   # don't panic if we can't find it
            video_thumbnail = compat_urllib_parse_unquote_plus(video_info['thumbnail_url'][0])

        # upload date
        upload_date = self._html_search_meta(
            'datePublished', video_webpage, 'upload date', default=None)
        if not upload_date:
            upload_date = self._search_regex(
                [r'(?s)id="eow-date.*?>(.*?)</span>',
                 r'id="watch-uploader-info".*?>.*?(?:Published|Uploaded|Streamed live|Started) on (.+?)</strong>'],
                video_webpage, 'upload date', default=None)
            if upload_date:
                upload_date = ' '.join(re.sub(r'[/,-]', r' ', mobj.group(1)).split())
        upload_date = unified_strdate(upload_date)

        video_license = self._html_search_regex(
            r'<h4[^>]+class="title"[^>]*>\s*License\s*</h4>\s*<ul[^>]*>\s*<li>(.+?)</li',
            video_webpage, 'license', default=None)

        m_music = re.search(
            r'<h4[^>]+class="title"[^>]*>\s*Music\s*</h4>\s*<ul[^>]*>\s*<li>(?P<title>.+?) by (?P<creator>.+?)(?:\(.+?\))?</li',
            video_webpage)
        if m_music:
            video_alt_title = remove_quotes(unescapeHTML(m_music.group('title')))
            video_creator = clean_html(m_music.group('creator'))
        else:
            video_alt_title = video_creator = None

        m_cat_container = self._search_regex(
            r'(?s)<h4[^>]*>\s*Category\s*</h4>\s*<ul[^>]*>(.*?)</ul>',
            video_webpage, 'categories', default=None)
        if m_cat_container:
            category = self._html_search_regex(
                r'(?s)<a[^<]+>(.*?)</a>', m_cat_container, 'category',
                default=None)
            video_categories = None if category is None else [category]
        else:
            video_categories = None

        video_tags = [
            unescapeHTML(m.group('content'))
            for m in re.finditer(self._meta_regex('og:video:tag'), video_webpage)]

        def _extract_count(count_name):
            return str_to_int(self._search_regex(
                r'-%s-button[^>]+><span[^>]+class="yt-uix-button-content"[^>]*>([\d,]+)</span>'
                % re.escape(count_name),
                video_webpage, count_name, default=None))

        like_count = _extract_count('like')
        dislike_count = _extract_count('dislike')

        # subtitles
        video_subtitles = self.extract_subtitles(video_id, video_webpage)
        automatic_captions = self.extract_automatic_captions(video_id, video_webpage)

        if 'length_seconds' not in video_info:
            self._downloader.report_warning('unable to extract video duration')
            video_duration = None
        else:
            video_duration = int(compat_urllib_parse_unquote_plus(video_info['length_seconds'][0]))

        # annotations
        video_annotations = None
        if self._downloader.params.get('writeannotations', False):
            video_annotations = self._extract_annotations(video_id)

        def _map_to_format_list(urlmap):
            formats = []
            for itag, video_real_url in urlmap.items():
                dct = {
                    'format_id': itag,
                    'url': video_real_url,
                    'player_url': player_url,
                }
                if itag in self._formats:
                    dct.update(self._formats[itag])
                formats.append(dct)
            return formats

        if 'conn' in video_info and video_info['conn'][0].startswith('rtmp'):
            self.report_rtmp_download()
            formats = [{
                'format_id': '_rtmp',
                'protocol': 'rtmp',
                'url': video_info['conn'][0],
                'player_url': player_url,
            }]
        elif len(video_info.get('url_encoded_fmt_stream_map', [''])[0]) >= 1 or len(video_info.get('adaptive_fmts', [''])[0]) >= 1:
            encoded_url_map = video_info.get('url_encoded_fmt_stream_map', [''])[0] + ',' + video_info.get('adaptive_fmts', [''])[0]
            if 'rtmpe%3Dyes' in encoded_url_map:
                raise ExtractorError('rtmpe downloads are not supported, see https://github.com/rg3/youtube-dl/issues/343 for more information.', expected=True)
            formats_spec = {}
            fmt_list = video_info.get('fmt_list', [''])[0]
            if fmt_list:
                for fmt in fmt_list.split(','):
                    spec = fmt.split('/')
                    if len(spec) > 1:
                        width_height = spec[1].split('x')
                        if len(width_height) == 2:
                            formats_spec[spec[0]] = {
                                'resolution': spec[1],
                                'width': int_or_none(width_height[0]),
                                'height': int_or_none(width_height[1]),
                            }
            formats = []
            for url_data_str in encoded_url_map.split(','):
                url_data = compat_parse_qs(url_data_str)
                if 'itag' not in url_data or 'url' not in url_data:
                    continue
                format_id = url_data['itag'][0]
                url = url_data['url'][0]

                if 'sig' in url_data:
                    url += '&signature=' + url_data['sig'][0]
                elif 's' in url_data:
                    encrypted_sig = url_data['s'][0]
                    ASSETS_RE = r'"assets":.+?"js":\s*("[^"]+")'

                    jsplayer_url_json = self._search_regex(
                        ASSETS_RE,
                        embed_webpage if age_gate else video_webpage,
                        'JS player URL (1)', default=None)
                    if not jsplayer_url_json and not age_gate:
                        # We need the embed website after all
                        if embed_webpage is None:
                            embed_url = proto + '://www.youtube.com/embed/%s' % video_id
                            embed_webpage = self._download_webpage(
                                embed_url, video_id, 'Downloading embed webpage')
                        jsplayer_url_json = self._search_regex(
                            ASSETS_RE, embed_webpage, 'JS player URL')

                    player_url = json.loads(jsplayer_url_json)
                    if player_url is None:
                        player_url_json = self._search_regex(
                            r'ytplayer\.config.*?"url"\s*:\s*("[^"]+")',
                            video_webpage, 'age gate player URL')
                        player_url = json.loads(player_url_json)

                    if self._downloader.params.get('verbose'):
                        if player_url is None:
                            player_version = 'unknown'
                            player_desc = 'unknown'
                        else:
                            if player_url.endswith('swf'):
                                player_version = self._search_regex(
                                    r'-(.+?)(?:/watch_as3)?\.swf$', player_url,
                                    'flash player', fatal=False)
                                player_desc = 'flash player %s' % player_version
                            else:
                                player_version = self._search_regex(
                                    [r'html5player-([^/]+?)(?:/html5player(?:-new)?)?\.js', r'(?:www|player)-([^/]+)/base\.js'],
                                    player_url,
                                    'html5 player', fatal=False)
                                player_desc = 'html5 player %s' % player_version

                        parts_sizes = self._signature_cache_id(encrypted_sig)
                        self.to_screen('{%s} signature length %s, %s' %
                                       (format_id, parts_sizes, player_desc))

                    signature = self._decrypt_signature(
                        encrypted_sig, video_id, player_url, age_gate)
                    url += '&signature=' + signature
                if 'ratebypass' not in url:
                    url += '&ratebypass=yes'

                dct = {
                    'format_id': format_id,
                    'url': url,
                    'player_url': player_url,
                }
                if format_id in self._formats:
                    dct.update(self._formats[format_id])
                if format_id in formats_spec:
                    dct.update(formats_spec[format_id])

                # Some itags are not included in DASH manifest thus corresponding formats will
                # lack metadata (see https://github.com/rg3/youtube-dl/pull/5993).
                # Trying to extract metadata from url_encoded_fmt_stream_map entry.
                mobj = re.search(r'^(?P<width>\d+)[xX](?P<height>\d+)$', url_data.get('size', [''])[0])
                width, height = (int(mobj.group('width')), int(mobj.group('height'))) if mobj else (None, None)

                more_fields = {
                    'filesize': int_or_none(url_data.get('clen', [None])[0]),
                    'tbr': float_or_none(url_data.get('bitrate', [None])[0], 1000),
                    'width': width,
                    'height': height,
                    'fps': int_or_none(url_data.get('fps', [None])[0]),
                    'format_note': url_data.get('quality_label', [None])[0] or url_data.get('quality', [None])[0],
                }
                for key, value in more_fields.items():
                    if value:
                        dct[key] = value
                type_ = url_data.get('type', [None])[0]
                if type_:
                    type_split = type_.split(';')
                    kind_ext = type_split[0].split('/')
                    if len(kind_ext) == 2:
                        kind, _ = kind_ext
                        dct['ext'] = mimetype2ext(type_split[0])
                        if kind in ('audio', 'video'):
                            codecs = None
                            for mobj in re.finditer(
                                    r'(?P<key>[a-zA-Z_-]+)=(?P<quote>["\']?)(?P<val>.+?)(?P=quote)(?:;|$)', type_):
                                if mobj.group('key') == 'codecs':
                                    codecs = mobj.group('val')
                                    break
                            if codecs:
                                codecs = codecs.split(',')
                                if len(codecs) == 2:
                                    acodec, vcodec = codecs[1], codecs[0]
                                else:
                                    acodec, vcodec = (codecs[0], 'none') if kind == 'audio' else ('none', codecs[0])
                                dct.update({
                                    'acodec': acodec,
                                    'vcodec': vcodec,
                                })
                formats.append(dct)
        elif video_info.get('hlsvp'):
            manifest_url = video_info['hlsvp'][0]
            url_map = self._extract_from_m3u8(manifest_url, video_id)
            formats = _map_to_format_list(url_map)
            # Accept-Encoding header causes failures in live streams on Youtube and Youtube Gaming
            for a_format in formats:
                a_format.setdefault('http_headers', {})['Youtubedl-no-compression'] = 'True'
        else:
            unavailable_message = self._html_search_regex(
                r'(?s)<h1[^>]+id="unavailable-message"[^>]*>(.+?)</h1>',
                video_webpage, 'unavailable message', default=None)
            if unavailable_message:
                raise ExtractorError(unavailable_message, expected=True)
            raise ExtractorError('no conn, hlsvp or url_encoded_fmt_stream_map information found in video info')

        # Look for the DASH manifest
        if self._downloader.params.get('youtube_include_dash_manifest', True):
            dash_mpd_fatal = True
            for mpd_url in dash_mpds:
                dash_formats = {}
                try:
                    def decrypt_sig(mobj):
                        s = mobj.group(1)
                        dec_s = self._decrypt_signature(s, video_id, player_url, age_gate)
                        return '/signature/%s' % dec_s

                    mpd_url = re.sub(r'/s/([a-fA-F0-9\.]+)', decrypt_sig, mpd_url)

                    for df in self._extract_mpd_formats(
                            mpd_url, video_id, fatal=dash_mpd_fatal,
                            formats_dict=self._formats):
                        # Do not overwrite DASH format found in some previous DASH manifest
                        if df['format_id'] not in dash_formats:
                            dash_formats[df['format_id']] = df
                        # Additional DASH manifests may end up in HTTP Error 403 therefore
                        # allow them to fail without bug report message if we already have
                        # some DASH manifest succeeded. This is temporary workaround to reduce
                        # burst of bug reports until we figure out the reason and whether it
                        # can be fixed at all.
                        dash_mpd_fatal = False
                except (ExtractorError, KeyError) as e:
                    self.report_warning(
                        'Skipping DASH manifest: %r' % e, video_id)
                if dash_formats:
                    # Remove the formats we found through non-DASH, they
                    # contain less info and it can be wrong, because we use
                    # fixed values (for example the resolution). See
                    # https://github.com/rg3/youtube-dl/issues/5774 for an
                    # example.
                    formats = [f for f in formats if f['format_id'] not in dash_formats.keys()]
                    formats.extend(dash_formats.values())

        # Check for malformed aspect ratio
        stretched_m = re.search(
            r'<meta\s+property="og:video:tag".*?content="yt:stretch=(?P<w>[0-9]+):(?P<h>[0-9]+)">',
            video_webpage)
        if stretched_m:
            w = float(stretched_m.group('w'))
            h = float(stretched_m.group('h'))
            # yt:stretch may hold invalid ratio data (e.g. for Q39EVAstoRM ratio is 17:0).
            # We will only process correct ratios.
            if w > 0 and h > 0:
                ratio = w / h
                for f in formats:
                    if f.get('vcodec') != 'none':
                        f['stretched_ratio'] = ratio

        self._sort_formats(formats)

        self.mark_watched(video_id, video_info)

        return {
            'id': video_id,
            'uploader': video_uploader,
            'uploader_id': video_uploader_id,
            'uploader_url': video_uploader_url,
            'upload_date': upload_date,
            'license': video_license,
            'creator': video_creator,
            'title': video_title,
            'alt_title': video_alt_title,
            'thumbnail': video_thumbnail,
            'description': video_description,
            'categories': video_categories,
            'tags': video_tags,
            'subtitles': video_subtitles,
            'automatic_captions': automatic_captions,
            'duration': video_duration,
            'age_limit': 18 if age_gate else 0,
            'annotations': video_annotations,
            'webpage_url': proto + '://www.youtube.com/watch?v=%s' % video_id,
            'view_count': view_count,
            'like_count': like_count,
            'dislike_count': dislike_count,
            'average_rating': float_or_none(video_info.get('avg_rating', [None])[0]),
            'formats': formats,
            'is_live': is_live,
            'start_time': start_time,
            'end_time': end_time,
        }


class YoutubeSharedVideoIE(InfoExtractor):
    _VALID_URL = r'(?:https?:)?//(?:www\.)?youtube\.com/shared\?.*\bci=(?P<id>[0-9A-Za-z_-]{11})'
    IE_NAME = 'youtube:shared'

    _TEST = {
        'url': 'https://www.youtube.com/shared?ci=1nEzmT-M4fU',
        'info_dict': {
            'id': 'uPDB5I9wfp8',
            'ext': 'webm',
            'title': 'Pocoyo: 90 minutos de episódios completos Português para crianças - PARTE 3',
            'description': 'md5:d9e4d9346a2dfff4c7dc4c8cec0f546d',
            'upload_date': '20160219',
            'uploader': 'Pocoyo - Português (BR)',
            'uploader_id': 'PocoyoBrazil',
        },
        'add_ie': ['Youtube'],
        'params': {
            # There are already too many Youtube downloads
            'skip_download': True,
        },
    }

    def _real_extract(self, url):
        video_id = self._match_id(url)

        webpage = self._download_webpage(url, video_id)

        real_video_id = self._html_search_meta(
            'videoId', webpage, 'YouTube video id', fatal=True)

        return self.url_result(real_video_id, YoutubeIE.ie_key())


class YoutubePlaylistIE(YoutubePlaylistBaseInfoExtractor):
    IE_DESC = 'YouTube.com playlists'
    _VALID_URL = r"""(?x)(?:
                        (?:https?://)?
                        (?:\w+\.)?
                        youtube\.com/
                        (?:
                           (?:course|view_play_list|my_playlists|artist|playlist|watch|embed/videoseries)
                           \? (?:.*?[&;])*? (?:p|a|list)=
                        |  p/
                        )
                        (
                            (?:PL|LL|EC|UU|FL|RD|UL)?[0-9A-Za-z-_]{10,}
                            # Top tracks, they can also include dots
                            |(?:MC)[\w\.]*
                        )
                        .*
                     |
                        ((?:PL|LL|EC|UU|FL|RD|UL)[0-9A-Za-z-_]{10,})
                     )"""
    _TEMPLATE_URL = 'https://www.youtube.com/playlist?list=%s'
    _VIDEO_RE = r'href="\s*/watch\?v=(?P<id>[0-9A-Za-z_-]{11})&amp;[^"]*?index=(?P<index>\d+)(?:[^>]+>(?P<title>[^<]+))?'
    IE_NAME = 'youtube:playlist'
    _TESTS = [{
        'url': 'https://www.youtube.com/playlist?list=PLwiyx1dc3P2JR9N8gQaQN_BCvlSlap7re',
        'info_dict': {
            'title': 'ytdl test PL',
            'id': 'PLwiyx1dc3P2JR9N8gQaQN_BCvlSlap7re',
        },
        'playlist_count': 3,
    }, {
        'url': 'https://www.youtube.com/playlist?list=PLtPgu7CB4gbZDA7i_euNxn75ISqxwZPYx',
        'info_dict': {
            'id': 'PLtPgu7CB4gbZDA7i_euNxn75ISqxwZPYx',
            'title': 'YDL_Empty_List',
        },
        'playlist_count': 0,
    }, {
        'note': 'Playlist with deleted videos (#651). As a bonus, the video #51 is also twice in this list.',
        'url': 'https://www.youtube.com/playlist?list=PLwP_SiAcdui0KVebT0mU9Apz359a4ubsC',
        'info_dict': {
            'title': '29C3: Not my department',
            'id': 'PLwP_SiAcdui0KVebT0mU9Apz359a4ubsC',
        },
        'playlist_count': 95,
    }, {
        'note': 'issue #673',
        'url': 'PLBB231211A4F62143',
        'info_dict': {
            'title': '[OLD]Team Fortress 2 (Class-based LP)',
            'id': 'PLBB231211A4F62143',
        },
        'playlist_mincount': 26,
    }, {
        'note': 'Large playlist',
        'url': 'https://www.youtube.com/playlist?list=UUBABnxM4Ar9ten8Mdjj1j0Q',
        'info_dict': {
            'title': 'Uploads from Cauchemar',
            'id': 'UUBABnxM4Ar9ten8Mdjj1j0Q',
        },
        'playlist_mincount': 799,
    }, {
        'url': 'PLtPgu7CB4gbY9oDN3drwC3cMbJggS7dKl',
        'info_dict': {
            'title': 'YDL_safe_search',
            'id': 'PLtPgu7CB4gbY9oDN3drwC3cMbJggS7dKl',
        },
        'playlist_count': 2,
    }, {
        'note': 'embedded',
        'url': 'http://www.youtube.com/embed/videoseries?list=PL6IaIsEjSbf96XFRuNccS_RuEXwNdsoEu',
        'playlist_count': 4,
        'info_dict': {
            'title': 'JODA15',
            'id': 'PL6IaIsEjSbf96XFRuNccS_RuEXwNdsoEu',
        }
    }, {
        'note': 'Embedded SWF player',
        'url': 'http://www.youtube.com/p/YN5VISEtHet5D4NEvfTd0zcgFk84NqFZ?hl=en_US&fs=1&rel=0',
        'playlist_count': 4,
        'info_dict': {
            'title': 'JODA7',
            'id': 'YN5VISEtHet5D4NEvfTd0zcgFk84NqFZ',
        }
    }, {
        'note': 'Buggy playlist: the webpage has a "Load more" button but it doesn\'t have more videos',
        'url': 'https://www.youtube.com/playlist?list=UUXw-G3eDE9trcvY2sBMM_aA',
        'info_dict': {
            'title': 'Uploads from Interstellar Movie',
            'id': 'UUXw-G3eDE9trcvY2sBMM_aA',
        },
        'playlist_mincout': 21,
    }]

    def _real_initialize(self):
        self._login()

    def _extract_mix(self, playlist_id):
        # The mixes are generated from a single video
        # the id of the playlist is just 'RD' + video_id
        ids = []
        last_id = playlist_id[-11:]
        for n in itertools.count(1):
            url = 'https://youtube.com/watch?v=%s&list=%s' % (last_id, playlist_id)
            webpage = self._download_webpage(
                url, playlist_id, 'Downloading page {0} of Youtube mix'.format(n))
            new_ids = orderedSet(re.findall(
                r'''(?xs)data-video-username=".*?".*?
                           href="/watch\?v=([0-9A-Za-z_-]{11})&amp;[^"]*?list=%s''' % re.escape(playlist_id),
                webpage))
            # Fetch new pages until all the videos are repeated, it seems that
            # there are always 51 unique videos.
            new_ids = [_id for _id in new_ids if _id not in ids]
            if not new_ids:
                break
            ids.extend(new_ids)
            last_id = ids[-1]

        url_results = self._ids_to_results(ids)

        search_title = lambda class_name: get_element_by_attribute('class', class_name, webpage)
        title_span = (
            search_title('playlist-title') or
            search_title('title long-title') or
            search_title('title'))
        title = clean_html(title_span)

        return self.playlist_result(url_results, playlist_id, title)

    def _extract_playlist(self, playlist_id):
        url = self._TEMPLATE_URL % playlist_id
        page = self._download_webpage(url, playlist_id)

        for match in re.findall(r'<div class="yt-alert-message">([^<]+)</div>', page):
            match = match.strip()
            # Check if the playlist exists or is private
            if re.match(r'[^<]*(The|This) playlist (does not exist|is private)[^<]*', match):
                raise ExtractorError(
                    'The playlist doesn\'t exist or is private, use --username or '
                    '--netrc to access it.',
                    expected=True)
            elif re.match(r'[^<]*Invalid parameters[^<]*', match):
                raise ExtractorError(
                    'Invalid parameters. Maybe URL is incorrect.',
                    expected=True)
            elif re.match(r'[^<]*Choose your language[^<]*', match):
                continue
            else:
                self.report_warning('Youtube gives an alert message: ' + match)

        playlist_title = self._html_search_regex(
            r'(?s)<h1 class="pl-header-title[^"]*"[^>]*>\s*(.*?)\s*</h1>',
            page, 'title')

        return self.playlist_result(self._entries(page, playlist_id), playlist_id, playlist_title)

    def _check_download_just_video(self, url, playlist_id):
        # Check if it's a video-specific URL
        query_dict = compat_urlparse.parse_qs(compat_urlparse.urlparse(url).query)
        if 'v' in query_dict:
            video_id = query_dict['v'][0]
            if self._downloader.params.get('noplaylist'):
                self.to_screen('Downloading just video %s because of --no-playlist' % video_id)
                return self.url_result(video_id, 'Youtube', video_id=video_id)
            else:
                self.to_screen('Downloading playlist %s - add --no-playlist to just download video %s' % (playlist_id, video_id))

    def _real_extract(self, url):
        # Extract playlist id
        mobj = re.match(self._VALID_URL, url)
        if mobj is None:
            raise ExtractorError('Invalid URL: %s' % url)
        playlist_id = mobj.group(1) or mobj.group(2)

        video = self._check_download_just_video(url, playlist_id)
        if video:
            return video

        if playlist_id.startswith(('RD', 'UL', 'PU')):
            # Mixes require a custom extraction process
            return self._extract_mix(playlist_id)

        return self._extract_playlist(playlist_id)


class YoutubeChannelIE(YoutubePlaylistBaseInfoExtractor):
    IE_DESC = 'YouTube.com channels'
    _VALID_URL = r'https?://(?:youtu\.be|(?:\w+\.)?youtube(?:-nocookie)?\.com)/channel/(?P<id>[0-9A-Za-z_-]+)'
    _TEMPLATE_URL = 'https://www.youtube.com/channel/%s/videos'
    _VIDEO_RE = r'(?:title="(?P<title>[^"]+)"[^>]+)?href="/watch\?v=(?P<id>[0-9A-Za-z_-]+)&?'
    IE_NAME = 'youtube:channel'
    _TESTS = [{
        'note': 'paginated channel',
        'url': 'https://www.youtube.com/channel/UCKfVa3S1e4PHvxWcwyMMg8w',
        'playlist_mincount': 91,
        'info_dict': {
            'id': 'UUKfVa3S1e4PHvxWcwyMMg8w',
            'title': 'Uploads from lex will',
        }
    }, {
        'note': 'Age restricted channel',
        # from https://www.youtube.com/user/DeusExOfficial
        'url': 'https://www.youtube.com/channel/UCs0ifCMCm1icqRbqhUINa0w',
        'playlist_mincount': 64,
        'info_dict': {
            'id': 'UUs0ifCMCm1icqRbqhUINa0w',
            'title': 'Uploads from Deus Ex',
        },
    }]

    @classmethod
    def suitable(cls, url):
        return (False if YoutubePlaylistsIE.suitable(url) or YoutubeLiveIE.suitable(url)
                else super(YoutubeChannelIE, cls).suitable(url))

    def _build_template_url(self, url, channel_id):
        return self._TEMPLATE_URL % channel_id

    def _real_extract(self, url):
        channel_id = self._match_id(url)

        url = self._build_template_url(url, channel_id)

        # Channel by page listing is restricted to 35 pages of 30 items, i.e. 1050 videos total (see #5778)
        # Workaround by extracting as a playlist if managed to obtain channel playlist URL
        # otherwise fallback on channel by page extraction
        channel_page = self._download_webpage(
            url + '?view=57', channel_id,
            'Downloading channel page', fatal=False)
        if channel_page is False:
            channel_playlist_id = False
        else:
            channel_playlist_id = self._html_search_meta(
                'channelId', channel_page, 'channel id', default=None)
            if not channel_playlist_id:
                channel_url = self._html_search_meta(
                    ('al:ios:url', 'twitter:app:url:iphone', 'twitter:app:url:ipad'),
                    channel_page, 'channel url', default=None)
                if channel_url:
                    channel_playlist_id = self._search_regex(
                        r'vnd\.youtube://user/([0-9A-Za-z_-]+)',
                        channel_url, 'channel id', default=None)
        if channel_playlist_id and channel_playlist_id.startswith('UC'):
            playlist_id = 'UU' + channel_playlist_id[2:]
            return self.url_result(
                compat_urlparse.urljoin(url, '/playlist?list=%s' % playlist_id), 'YoutubePlaylist')

        channel_page = self._download_webpage(url, channel_id, 'Downloading page #1')
        autogenerated = re.search(r'''(?x)
                class="[^"]*?(?:
                    channel-header-autogenerated-label|
                    yt-channel-title-autogenerated
                )[^"]*"''', channel_page) is not None

        if autogenerated:
            # The videos are contained in a single page
            # the ajax pages can't be used, they are empty
            entries = [
                self.url_result(
                    video_id, 'Youtube', video_id=video_id,
                    video_title=video_title)
                for video_id, video_title in self.extract_videos_from_page(channel_page)]
            return self.playlist_result(entries, channel_id)

        try:
            next(self._entries(channel_page, channel_id))
        except StopIteration:
            alert_message = self._html_search_regex(
                r'(?s)<div[^>]+class=(["\']).*?\byt-alert-message\b.*?\1[^>]*>(?P<alert>[^<]+)</div>',
                channel_page, 'alert', default=None, group='alert')
            if alert_message:
                raise ExtractorError('Youtube said: %s' % alert_message, expected=True)

        return self.playlist_result(self._entries(channel_page, channel_id), channel_id)


class YoutubeUserIE(YoutubeChannelIE):
    IE_DESC = 'YouTube.com user videos (URL or "ytuser" keyword)'
    _VALID_URL = r'(?:(?:https?://(?:\w+\.)?youtube\.com/(?:(?P<user>user|c)/)?(?!(?:attribution_link|watch|results)(?:$|[^a-z_A-Z0-9-])))|ytuser:)(?!feed/)(?P<id>[A-Za-z0-9_-]+)'
    _TEMPLATE_URL = 'https://www.youtube.com/%s/%s/videos'
    IE_NAME = 'youtube:user'

    _TESTS = [{
        'url': 'https://www.youtube.com/user/TheLinuxFoundation',
        'playlist_mincount': 320,
        'info_dict': {
            'id': 'UUfX55Sx5hEFjoC3cNs6mCUQ',
            'title': 'Uploads from The Linux Foundation',
        }
    }, {
        # Only available via https://www.youtube.com/c/12minuteathlete/videos
        # but not https://www.youtube.com/user/12minuteathlete/videos
        'url': 'https://www.youtube.com/c/12minuteathlete/videos',
        'playlist_mincount': 249,
        'info_dict': {
            'id': 'UUVjM-zV6_opMDx7WYxnjZiQ',
            'title': 'Uploads from 12 Minute Athlete',
        }
    }, {
        'url': 'ytuser:phihag',
        'only_matching': True,
    }, {
        'url': 'https://www.youtube.com/c/gametrailers',
        'only_matching': True,
    }, {
        'url': 'https://www.youtube.com/gametrailers',
        'only_matching': True,
    }, {
        # This channel is not available.
        'url': 'https://www.youtube.com/user/kananishinoSMEJ/videos',
        'only_matching': True,
    }]

    @classmethod
    def suitable(cls, url):
        # Don't return True if the url can be extracted with other youtube
        # extractor, the regex would is too permissive and it would match.
        other_yt_ies = iter(klass for (name, klass) in globals().items() if name.startswith('Youtube') and name.endswith('IE') and klass is not cls)
        if any(ie.suitable(url) for ie in other_yt_ies):
            return False
        else:
            return super(YoutubeUserIE, cls).suitable(url)

    def _build_template_url(self, url, channel_id):
        mobj = re.match(self._VALID_URL, url)
        return self._TEMPLATE_URL % (mobj.group('user') or 'user', mobj.group('id'))


class YoutubeLiveIE(YoutubeBaseInfoExtractor):
    IE_DESC = 'YouTube.com live streams'
    _VALID_URL = r'(?P<base_url>https?://(?:\w+\.)?youtube\.com/(?:user|channel)/(?P<id>[^/]+))/live'
    IE_NAME = 'youtube:live'

    _TESTS = [{
        'url': 'http://www.youtube.com/user/TheYoungTurks/live',
        'info_dict': {
            'id': 'a48o2S1cPoo',
            'ext': 'mp4',
            'title': 'The Young Turks - Live Main Show',
            'uploader': 'The Young Turks',
            'uploader_id': 'TheYoungTurks',
            'uploader_url': 're:https?://(?:www\.)?youtube\.com/user/TheYoungTurks',
            'upload_date': '20150715',
            'license': 'Standard YouTube License',
            'description': 'md5:438179573adcdff3c97ebb1ee632b891',
            'categories': ['News & Politics'],
            'tags': ['Cenk Uygur (TV Program Creator)', 'The Young Turks (Award-Winning Work)', 'Talk Show (TV Genre)'],
            'like_count': int,
            'dislike_count': int,
        },
        'params': {
            'skip_download': True,
        },
    }, {
        'url': 'http://www.youtube.com/channel/UC1yBKRuGpC1tSM73A0ZjYjQ/live',
        'only_matching': True,
    }]

    def _real_extract(self, url):
        mobj = re.match(self._VALID_URL, url)
        channel_id = mobj.group('id')
        base_url = mobj.group('base_url')
        webpage = self._download_webpage(url, channel_id, fatal=False)
        if webpage:
            page_type = self._og_search_property(
                'type', webpage, 'page type', default=None)
            video_id = self._html_search_meta(
                'videoId', webpage, 'video id', default=None)
            if page_type == 'video' and video_id and re.match(r'^[0-9A-Za-z_-]{11}$', video_id):
                return self.url_result(video_id, YoutubeIE.ie_key())
        return self.url_result(base_url)


class YoutubePlaylistsIE(YoutubePlaylistsBaseInfoExtractor):
    IE_DESC = 'YouTube.com user/channel playlists'
    _VALID_URL = r'https?://(?:\w+\.)?youtube\.com/(?:user|channel)/(?P<id>[^/]+)/playlists'
    IE_NAME = 'youtube:playlists'

    _TESTS = [{
        'url': 'http://www.youtube.com/user/ThirstForScience/playlists',
        'playlist_mincount': 4,
        'info_dict': {
            'id': 'ThirstForScience',
            'title': 'Thirst for Science',
        },
    }, {
        # with "Load more" button
        'url': 'http://www.youtube.com/user/igorkle1/playlists?view=1&sort=dd',
        'playlist_mincount': 70,
        'info_dict': {
            'id': 'igorkle1',
            'title': 'Игорь Клейнер',
        },
    }, {
        'url': 'https://www.youtube.com/channel/UCiU1dHvZObB2iP6xkJ__Icw/playlists',
        'playlist_mincount': 17,
        'info_dict': {
            'id': 'UCiU1dHvZObB2iP6xkJ__Icw',
            'title': 'Chem Player',
        },
    }]


class YoutubeSearchIE(SearchInfoExtractor, YoutubePlaylistIE):
    IE_DESC = 'YouTube.com searches'
    # there doesn't appear to be a real limit, for example if you search for
    # 'python' you get more than 8.000.000 results
    _MAX_RESULTS = float('inf')
    IE_NAME = 'youtube:search'
    _SEARCH_KEY = 'ytsearch'
    _EXTRA_QUERY_ARGS = {}
    _TESTS = []

    def _get_n_results(self, query, n):
        """Get a specified number of results for a query"""

        videos = []
        limit = n

        for pagenum in itertools.count(1):
            url_query = {
                'search_query': query.encode('utf-8'),
                'page': pagenum,
                'spf': 'navigate',
            }
            url_query.update(self._EXTRA_QUERY_ARGS)
            result_url = 'https://www.youtube.com/results?' + compat_urllib_parse_urlencode(url_query)
            data = self._download_json(
                result_url, video_id='query "%s"' % query,
                note='Downloading page %s' % pagenum,
                errnote='Unable to download API page')
            html_content = data[1]['body']['content']

            if 'class="search-message' in html_content:
                raise ExtractorError(
                    '[youtube] No video results', expected=True)

            new_videos = self._ids_to_results(orderedSet(re.findall(
                r'href="/watch\?v=(.{11})', html_content)))
            videos += new_videos
            if not new_videos or len(videos) > limit:
                break

        if len(videos) > n:
            videos = videos[:n]
        return self.playlist_result(videos, query)


class YoutubeSearchDateIE(YoutubeSearchIE):
    IE_NAME = YoutubeSearchIE.IE_NAME + ':date'
    _SEARCH_KEY = 'ytsearchdate'
    IE_DESC = 'YouTube.com searches, newest videos first'
    _EXTRA_QUERY_ARGS = {'search_sort': 'video_date_uploaded'}


class YoutubeSearchURLIE(YoutubePlaylistBaseInfoExtractor):
    IE_DESC = 'YouTube.com search URLs'
    IE_NAME = 'youtube:search_url'
    _VALID_URL = r'https?://(?:www\.)?youtube\.com/results\?(.*?&)?(?:search_query|q)=(?P<query>[^&]+)(?:[&]|$)'
    _VIDEO_RE = r'href="\s*/watch\?v=(?P<id>[0-9A-Za-z_-]{11})(?:[^"]*"[^>]+\btitle="(?P<title>[^"]+))?'
    _TESTS = [{
        'url': 'https://www.youtube.com/results?baz=bar&search_query=youtube-dl+test+video&filters=video&lclk=video',
        'playlist_mincount': 5,
        'info_dict': {
            'title': 'youtube-dl test video',
        }
    }, {
        'url': 'https://www.youtube.com/results?q=test&sp=EgQIBBgB',
        'only_matching': True,
    }]

    def _real_extract(self, url):
        mobj = re.match(self._VALID_URL, url)
        query = compat_urllib_parse_unquote_plus(mobj.group('query'))
        webpage = self._download_webpage(url, query)
        return self.playlist_result(self._process_page(webpage), playlist_title=query)


class YoutubeShowIE(YoutubePlaylistsBaseInfoExtractor):
    IE_DESC = 'YouTube.com (multi-season) shows'
    _VALID_URL = r'https?://www\.youtube\.com/show/(?P<id>[^?#]*)'
    IE_NAME = 'youtube:show'
    _TESTS = [{
        'url': 'https://www.youtube.com/show/airdisasters',
        'playlist_mincount': 5,
        'info_dict': {
            'id': 'airdisasters',
            'title': 'Air Disasters',
        }
    }]

    def _real_extract(self, url):
        playlist_id = self._match_id(url)
        return super(YoutubeShowIE, self)._real_extract(
            'https://www.youtube.com/show/%s/playlists' % playlist_id)


class YoutubeFeedsInfoExtractor(YoutubeBaseInfoExtractor):
    """
    Base class for feed extractors
    Subclasses must define the _FEED_NAME and _PLAYLIST_TITLE properties.
    """
    _LOGIN_REQUIRED = True

    @property
    def IE_NAME(self):
        return 'youtube:%s' % self._FEED_NAME

    def _real_initialize(self):
        self._login()

    def _real_extract(self, url):
        page = self._download_webpage(
            'https://www.youtube.com/feed/%s' % self._FEED_NAME, self._PLAYLIST_TITLE)

        # The extraction process is the same as for playlists, but the regex
        # for the video ids doesn't contain an index
        ids = []
        more_widget_html = content_html = page
        for page_num in itertools.count(1):
            matches = re.findall(r'href="\s*/watch\?v=([0-9A-Za-z_-]{11})', content_html)

            # 'recommended' feed has infinite 'load more' and each new portion spins
            # the same videos in (sometimes) slightly different order, so we'll check
            # for unicity and break when portion has no new videos
            new_ids = filter(lambda video_id: video_id not in ids, orderedSet(matches))
            if not new_ids:
                break

            ids.extend(new_ids)

            mobj = re.search(r'data-uix-load-more-href="/?(?P<more>[^"]+)"', more_widget_html)
            if not mobj:
                break

            more = self._download_json(
                'https://youtube.com/%s' % mobj.group('more'), self._PLAYLIST_TITLE,
                'Downloading page #%s' % page_num,
                transform_source=uppercase_escape)
            content_html = more['content_html']
            more_widget_html = more['load_more_widget_html']

        return self.playlist_result(
            self._ids_to_results(ids), playlist_title=self._PLAYLIST_TITLE)


class YoutubeWatchLaterIE(YoutubePlaylistIE):
    IE_NAME = 'youtube:watchlater'
    IE_DESC = 'Youtube watch later list, ":ytwatchlater" for short (requires authentication)'
    _VALID_URL = r'https?://www\.youtube\.com/(?:feed/watch_later|(?:playlist|watch)\?(?:.+&)?list=WL)|:ytwatchlater'

    _TESTS = [{
        'url': 'https://www.youtube.com/playlist?list=WL',
        'only_matching': True,
    }, {
        'url': 'https://www.youtube.com/watch?v=bCNU9TrbiRk&index=1&list=WL',
        'only_matching': True,
    }]

    def _real_extract(self, url):
        video = self._check_download_just_video(url, 'WL')
        if video:
            return video
        return self._extract_playlist('WL')


class YoutubeFavouritesIE(YoutubeBaseInfoExtractor):
    IE_NAME = 'youtube:favorites'
    IE_DESC = 'YouTube.com favourite videos, ":ytfav" for short (requires authentication)'
    _VALID_URL = r'https?://www\.youtube\.com/my_favorites|:ytfav(?:ou?rites)?'
    _LOGIN_REQUIRED = True

    def _real_extract(self, url):
        webpage = self._download_webpage('https://www.youtube.com/my_favorites', 'Youtube Favourites videos')
        playlist_id = self._search_regex(r'list=(.+?)["&]', webpage, 'favourites playlist id')
        return self.url_result(playlist_id, 'YoutubePlaylist')


class YoutubeRecommendedIE(YoutubeFeedsInfoExtractor):
    IE_DESC = 'YouTube.com recommended videos, ":ytrec" for short (requires authentication)'
    _VALID_URL = r'https?://www\.youtube\.com/feed/recommended|:ytrec(?:ommended)?'
    _FEED_NAME = 'recommended'
    _PLAYLIST_TITLE = 'Youtube Recommended videos'


class YoutubeSubscriptionsIE(YoutubeFeedsInfoExtractor):
    IE_DESC = 'YouTube.com subscriptions feed, "ytsubs" keyword (requires authentication)'
    _VALID_URL = r'https?://www\.youtube\.com/feed/subscriptions|:ytsubs(?:criptions)?'
    _FEED_NAME = 'subscriptions'
    _PLAYLIST_TITLE = 'Youtube Subscriptions'


class YoutubeHistoryIE(YoutubeFeedsInfoExtractor):
    IE_DESC = 'Youtube watch history, ":ythistory" for short (requires authentication)'
    _VALID_URL = 'https?://www\.youtube\.com/feed/history|:ythistory'
    _FEED_NAME = 'history'
    _PLAYLIST_TITLE = 'Youtube History'


class YoutubeTruncatedURLIE(InfoExtractor):
    IE_NAME = 'youtube:truncated_url'
    IE_DESC = False  # Do not list
    _VALID_URL = r'''(?x)
        (?:https?://)?
        (?:\w+\.)?[yY][oO][uU][tT][uU][bB][eE](?:-nocookie)?\.com/
        (?:watch\?(?:
            feature=[a-z_]+|
            annotation_id=annotation_[^&]+|
            x-yt-cl=[0-9]+|
            hl=[^&]*|
            t=[0-9]+
        )?
        |
            attribution_link\?a=[^&]+
        )
        $
    '''

    _TESTS = [{
        'url': 'http://www.youtube.com/watch?annotation_id=annotation_3951667041',
        'only_matching': True,
    }, {
        'url': 'http://www.youtube.com/watch?',
        'only_matching': True,
    }, {
        'url': 'https://www.youtube.com/watch?x-yt-cl=84503534',
        'only_matching': True,
    }, {
        'url': 'https://www.youtube.com/watch?feature=foo',
        'only_matching': True,
    }, {
        'url': 'https://www.youtube.com/watch?hl=en-GB',
        'only_matching': True,
    }, {
        'url': 'https://www.youtube.com/watch?t=2372',
        'only_matching': True,
    }]

    def _real_extract(self, url):
        raise ExtractorError(
            'Did you forget to quote the URL? Remember that & is a meta '
            'character in most shells, so you want to put the URL in quotes, '
            'like  youtube-dl '
            '"http://www.youtube.com/watch?feature=foo&v=BaW_jenozKc" '
            ' or simply  youtube-dl BaW_jenozKc  .',
            expected=True)


class YoutubeTruncatedIDIE(InfoExtractor):
    IE_NAME = 'youtube:truncated_id'
    IE_DESC = False  # Do not list
    _VALID_URL = r'https?://(?:www\.)?youtube\.com/watch\?v=(?P<id>[0-9A-Za-z_-]{1,10})$'

    _TESTS = [{
        'url': 'https://www.youtube.com/watch?v=N_708QY7Ob',
        'only_matching': True,
    }]

    def _real_extract(self, url):
        video_id = self._match_id(url)
        raise ExtractorError(
            'Incomplete YouTube ID %s. URL %s looks truncated.' % (video_id, url),
            expected=True)
