aboutsummaryrefslogtreecommitdiff
path: root/youtube_dl/extractor/youtube.py
blob: 7d6d07b17840247f8f873f0f6e3aa564d2a394c6 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
# coding: utf-8

import json
import netrc
import re
import socket
import itertools

from .common import InfoExtractor, SearchInfoExtractor
from ..utils import (
    compat_http_client,
    compat_parse_qs,
    compat_urllib_error,
    compat_urllib_parse,
    compat_urllib_request,
    compat_str,

    clean_html,
    get_element_by_id,
    ExtractorError,
    unescapeHTML,
    unified_strdate,
    orderedSet,
)

class YoutubeBaseInfoExtractor(InfoExtractor):
    """Provide base functions for Youtube extractors"""
    _LOGIN_URL = 'https://accounts.google.com/ServiceLogin'
    _LANG_URL = r'https://www.youtube.com/?hl=en&persist_hl=1&gl=US&persist_gl=1&opt_out_ackd=1'
    _AGE_URL = 'http://www.youtube.com/verify_age?next_url=/&gl=US&hl=en'
    _NETRC_MACHINE = 'youtube'
    # If True it will raise an error if no login info is provided
    _LOGIN_REQUIRED = False

    def report_lang(self):
        """Report attempt to set language."""
        self.to_screen(u'Setting language')

    def _set_language(self):
        request = compat_urllib_request.Request(self._LANG_URL)
        try:
            self.report_lang()
            compat_urllib_request.urlopen(request).read()
        except (compat_urllib_error.URLError, compat_http_client.HTTPException, socket.error) as err:
            self._downloader.report_warning(u'unable to set language: %s' % compat_str(err))
            return False
        return True

    def _login(self):
        (username, password) = self._get_login_info()
        # No authentication to be performed
        if username is None:
            if self._LOGIN_REQUIRED:
                raise ExtractorError(u'No login info available, needed for using %s.' % self.IE_NAME, expected=True)
            return False

        request = compat_urllib_request.Request(self._LOGIN_URL)
        try:
            login_page = compat_urllib_request.urlopen(request).read().decode('utf-8')
        except (compat_urllib_error.URLError, compat_http_client.HTTPException, socket.error) as err:
            self._downloader.report_warning(u'unable to fetch login page: %s' % compat_str(err))
            return False

        galx = None
        dsh = None
        match = re.search(re.compile(r'<input.+?name="GALX".+?value="(.+?)"', re.DOTALL), login_page)
        if match:
          galx = match.group(1)
        match = re.search(re.compile(r'<input.+?name="dsh".+?value="(.+?)"', re.DOTALL), login_page)
        if match:
          dsh = match.group(1)

        # Log in
        login_form_strs = {
                u'continue': u'https://www.youtube.com/signin?action_handle_signin=true&feature=sign_in_button&hl=en_US&nomobiletemp=1',
                u'Email': username,
                u'GALX': galx,
                u'Passwd': password,
                u'PersistentCookie': u'yes',
                u'_utf8': u'霱',
                u'bgresponse': u'js_disabled',
                u'checkConnection': u'',
                u'checkedDomains': u'youtube',
                u'dnConn': u'',
                u'dsh': dsh,
                u'pstMsg': u'0',
                u'rmShown': u'1',
                u'secTok': u'',
                u'signIn': u'Sign in',
                u'timeStmp': u'',
                u'service': u'youtube',
                u'uilel': u'3',
                u'hl': u'en_US',
        }
        # Convert to UTF-8 *before* urlencode because Python 2.x's urlencode
        # chokes on unicode
        login_form = dict((k.encode('utf-8'), v.encode('utf-8')) for k,v in login_form_strs.items())
        login_data = compat_urllib_parse.urlencode(login_form).encode('ascii')
        request = compat_urllib_request.Request(self._LOGIN_URL, login_data)
        try:
            self.report_login()
            login_results = compat_urllib_request.urlopen(request).read().decode('utf-8')
            if re.search(r'(?i)<form[^>]* id="gaia_loginform"', login_results) is not None:
                self._downloader.report_warning(u'unable to log in: bad username or password')
                return False
        except (compat_urllib_error.URLError, compat_http_client.HTTPException, socket.error) as err:
            self._downloader.report_warning(u'unable to log in: %s' % compat_str(err))
            return False
        return True

    def _confirm_age(self):
        age_form = {
                'next_url':     '/',
                'action_confirm':   'Confirm',
                }
        request = compat_urllib_request.Request(self._AGE_URL, compat_urllib_parse.urlencode(age_form))
        try:
            self.report_age_confirmation()
            compat_urllib_request.urlopen(request).read().decode('utf-8')
        except (compat_urllib_error.URLError, compat_http_client.HTTPException, socket.error) as err:
            raise ExtractorError(u'Unable to confirm age: %s' % compat_str(err))
        return True

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

class YoutubeIE(YoutubeBaseInfoExtractor):
    IE_DESC = u'YouTube.com'
    _VALID_URL = r"""^
                     (
                         (?:https?://)?                                       # http(s):// (optional)
                         (?:youtu\.be/|(?:\w+\.)?youtube(?:-nocookie)?\.com/|
                            tube\.majestyc\.net/)                             # the various hostnames, with wildcard subdomains
                         (?:.*?\#/)?                                          # handle anchor (#/) redirect urls
                         (?:                                                  # the various things that can precede the ID:
                             (?:(?:v|embed|e)/)                               # 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)
                                 v=
                             )
                         )?                                                   # optional -> youtube.com/xxxx is OK
                     )?                                                       # all until now is optional -> you can pass the naked ID
                     ([0-9A-Za-z_-]+)                                         # here is it! the YouTube video ID
                     (?(1).+)?                                                # if we found the ID, everything can follow
                     $"""
    _NEXT_URL_RE = r'[\?&]next_url=([^&]+)'
    # Listed in order of quality
    _available_formats = ['38', '37', '46', '22', '45', '35', '44', '34', '18', '43', '6', '5', '17', '13',
                          '95', '94', '93', '92', '132', '151',
                          '85', '84', '102', '83', '101', '82', '100',        # 3D
                          '138', '137', '136', '135', '134', '133', '160',    # Dash video mp4
                          '141', '140', '139',                                # Dash auido mp4
                          '248', '247', '246', '245', '244', '243', '242',    # Dash video webm
                          '172', '171',                                       # Dash audio webm
                          ]
    _available_formats_prefer_free = ['38', '46', '37', '45', '22', '44', '35', '43', '34', '18', '6', '5', '17', '13',
                                      '95', '94', '93', '92', '132', '151',
                                      '85', '102', '84', '101', '83', '100', '82',
                                      '248', '247', '246', '245', '244', '243', '242',    # Dash video webm
                                      '172', '171',                                       # Dash audio webm
                                      '138', '137', '136', '135', '134', '133', '160',    # Dash video mp4
                                      '141', '140', '139',                                # Dash auido mp4
                                      ]
    _video_extensions = {
        '13': '3gp',
        '17': 'mp4',
        '18': 'mp4',
        '22': 'mp4',
        '37': 'mp4',
        '38': 'mp4',
        '43': 'webm',
        '44': 'webm',
        '45': 'webm',
        '46': 'webm',

        # 3d videos
        '82': 'mp4',
        '83': 'mp4',
        '84': 'mp4',
        '85': 'mp4',
        '100': 'webm',
        '101': 'webm',
        '102': 'webm',

        # videos that use m3u8
        '92': 'mp4',
        '93': 'mp4',
        '94': 'mp4',
        '95': 'mp4',
        '96': 'mp4',
        '132': 'mp4',
        '151': 'mp4',

        # Dash mp4
        '133': 'mp4',
        '134': 'mp4',
        '135': 'mp4',
        '136': 'mp4',
        '137': 'mp4',
        '138': 'mp4',
        '139': 'mp4',
        '140': 'mp4',
        '141': 'mp4',
        '160': 'mp4',

        # Dash webm
        '171': 'webm',
        '172': 'webm',
        '242': 'webm',
        '243': 'webm',
        '244': 'webm',
        '245': 'webm',
        '246': 'webm',
        '247': 'webm',
        '248': 'webm',
    }
    _video_dimensions = {
        '5': '240x400',
        '6': '???',
        '13': '???',
        '17': '144x176',
        '18': '360x640',
        '22': '720x1280',
        '34': '360x640',
        '35': '480x854',
        '37': '1080x1920',
        '38': '3072x4096',
        '43': '360x640',
        '44': '480x854',
        '45': '720x1280',
        '46': '1080x1920',
        '82': '360p',
        '83': '480p',
        '84': '720p',
        '85': '1080p',
        '92': '240p',
        '93': '360p',
        '94': '480p',
        '95': '720p',
        '96': '1080p',
        '100': '360p',
        '101': '480p',
        '102': '720p',
        '132': '240p',
        '151': '72p',
        '133': '240p',
        '134': '360p',
        '135': '480p',
        '136': '720p',
        '137': '1080p',
        '138': '>1080p',
        '139': '48k',
        '140': '128k',
        '141': '256k',
        '160': '192p',
        '171': '128k',
        '172': '256k',
        '242': '240p',
        '243': '360p',
        '244': '480p',
        '245': '480p',
        '246': '480p',
        '247': '720p',
        '248': '1080p',
    }
    _special_itags = {
        '82': '3D',
        '83': '3D',
        '84': '3D',
        '85': '3D',
        '100': '3D',
        '101': '3D',
        '102': '3D',
        '133': 'DASH Video',
        '134': 'DASH Video',
        '135': 'DASH Video',
        '136': 'DASH Video',
        '137': 'DASH Video',
        '138': 'DASH Video',
        '139': 'DASH Audio',
        '140': 'DASH Audio',
        '141': 'DASH Audio',
        '160': 'DASH Video',
        '171': 'DASH Audio',
        '172': 'DASH Audio',
        '242': 'DASH Video',
        '243': 'DASH Video',
        '244': 'DASH Video',
        '245': 'DASH Video',
        '246': 'DASH Video',
        '247': 'DASH Video',
        '248': 'DASH Video',
    }

    IE_NAME = u'youtube'
    _TESTS = [
        {
            u"url":  u"http://www.youtube.com/watch?v=BaW_jenozKc",
            u"file":  u"BaW_jenozKc.mp4",
            u"info_dict": {
                u"title": u"youtube-dl test video \"'/\\ä↭𝕐",
                u"uploader": u"Philipp Hagemeister",
                u"uploader_id": u"phihag",
                u"upload_date": u"20121002",
                u"description": u"test chars:  \"'/\\ä↭𝕐\n\nThis is a test video for youtube-dl.\n\nFor more information, contact phihag@phihag.de ."
            }
        },
        {
            u"url":  u"http://www.youtube.com/watch?v=1ltcDfZMA3U",
            u"file":  u"1ltcDfZMA3U.flv",
            u"note": u"Test VEVO video (#897)",
            u"info_dict": {
                u"upload_date": u"20070518",
                u"title": u"Maps - It Will Find You",
                u"description": u"Music video by Maps performing It Will Find You.",
                u"uploader": u"MuteUSA",
                u"uploader_id": u"MuteUSA"
            }
        },
        {
            u"url":  u"http://www.youtube.com/watch?v=UxxajLWwzqY",
            u"file":  u"UxxajLWwzqY.mp4",
            u"note": u"Test generic use_cipher_signature video (#897)",
            u"info_dict": {
                u"upload_date": u"20120506",
                u"title": u"Icona Pop - I Love It (feat. Charli XCX) [OFFICIAL VIDEO]",
                u"description": u"md5:b085c9804f5ab69f4adea963a2dceb3c",
                u"uploader": u"Icona Pop",
                u"uploader_id": u"IconaPop"
            }
        },
        {
            u"url":  u"https://www.youtube.com/watch?v=07FYdnEawAQ",
            u"file":  u"07FYdnEawAQ.mp4",
            u"note": u"Test VEVO video with age protection (#956)",
            u"info_dict": {
                u"upload_date": u"20130703",
                u"title": u"Justin Timberlake - Tunnel Vision (Explicit)",
                u"description": u"md5:64249768eec3bc4276236606ea996373",
                u"uploader": u"justintimberlakeVEVO",
                u"uploader_id": u"justintimberlakeVEVO"
            }
        },
        {
            u'url': u'https://www.youtube.com/watch?v=TGi3HqYrWHE',
            u'file': u'TGi3HqYrWHE.mp4',
            u'note': u'm3u8 video',
            u'info_dict': {
                u'title': u'Triathlon - Men - London 2012 Olympic Games',
                u'description': u'- Men -  TR02 - Triathlon - 07 August 2012 - London 2012 Olympic Games',
                u'uploader': u'olympic',
                u'upload_date': u'20120807',
                u'uploader_id': u'olympic',
            },
            u'params': {
                u'skip_download': True,
            },
        },
    ]


    @classmethod
    def suitable(cls, url):
        """Receives a URL and returns True if suitable for this IE."""
        if YoutubePlaylistIE.suitable(url) or YoutubeSubscriptionsIE.suitable(url): return False
        return re.match(cls._VALID_URL, url, re.VERBOSE) is not None

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

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

    def report_video_subtitles_download(self, video_id):
        """Report attempt to download video info webpage."""
        self.to_screen(u'%s: Checking available subtitles' % video_id)

    def report_video_subtitles_request(self, video_id, sub_lang, format):
        """Report attempt to download video info webpage."""
        self.to_screen(u'%s: Downloading video subtitles for %s.%s' % (video_id, sub_lang, format))

    def report_video_subtitles_available(self, video_id, sub_lang_list):
        """Report available subtitles."""
        sub_lang = ",".join(list(sub_lang_list.keys()))
        self.to_screen(u'%s: Available subtitles for video: %s' % (video_id, sub_lang))

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

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

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

    def _decrypt_signature(self, s):
        """Turn the encrypted s field into a working signature"""

        if len(s) == 92:
            return s[25] + s[3:25] + s[0] + s[26:42] + s[79] + s[43:79] + s[91] + s[80:83]
        elif len(s) == 90:
            return s[25] + s[3:25] + s[2] + s[26:40] + s[77] + s[41:77] + s[89] + s[78:81]
        elif len(s) == 89:
            return s[84:78:-1] + s[87] + s[77:60:-1] + s[0] + s[59:3:-1]
        elif len(s) == 88:
            return s[48] + s[81:67:-1] + s[82] + s[66:62:-1] + s[85] + s[61:48:-1] + s[67] + s[47:12:-1] + s[3] + s[11:3:-1] + s[2] + s[12]
        elif len(s) == 87:
            return s[6:27] + s[4] + s[28:39] + s[27] + s[40:59] + s[2] + s[60:]
        elif len(s) == 86:
            return s[5:20] + s[2] + s[21:]
        elif len(s) == 85:
            return s[83:34:-1] + s[0] + s[33:27:-1] + s[3] + s[26:19:-1] + s[34] + s[18:3:-1] + s[27]
        elif len(s) == 84:
            return s[83:27:-1] + s[0] + s[26:5:-1] + s[2:0:-1] + s[27]
        elif len(s) == 83:
            return s[81:64:-1] + s[82] + s[63:52:-1] + s[45] + s[51:45:-1] + s[1] + s[44:1:-1] + s[0]
        elif len(s) == 82:
            return s[36] + s[79:67:-1] + s[81] + s[66:40:-1] + s[33] + s[39:36:-1] + s[40] + s[35] + s[0] + s[67] + s[32:0:-1] + s[34]
        elif len(s) == 81:
            return s[56] + s[79:56:-1] + s[41] + s[55:41:-1] + s[80] + s[40:34:-1] + s[0] + s[33:29:-1] + s[34] + s[28:9:-1] + s[29] + s[8:0:-1] + s[9]
        elif len(s) == 79:
            return s[54] + s[77:54:-1] + s[39] + s[53:39:-1] + s[78] + s[38:34:-1] + s[0] + s[33:29:-1] + s[34] + s[28:9:-1] + s[29] + s[8:0:-1] + s[9]

        else:
            raise ExtractorError(u'Unable to decrypt signature, key length %d not supported; retrying might work' % (len(s)))

    def _decrypt_signature_age_gate(self, s):
        # The videos with age protection use another player, so the algorithms
        # can be different.
        if len(s) == 86:
            return s[2:63] + s[82] + s[64:82] + s[63]
        else:
            # Fallback to the other algortihms
            return self._decrypt_signature(s)


    def _get_available_subtitles(self, video_id):
        self.report_video_subtitles_download(video_id)
        request = compat_urllib_request.Request('http://video.google.com/timedtext?hl=en&type=list&v=%s' % video_id)
        try:
            sub_list = compat_urllib_request.urlopen(request).read().decode('utf-8')
        except (compat_urllib_error.URLError, compat_http_client.HTTPException, socket.error) as err:
            return (u'unable to download video subtitles: %s' % compat_str(err), None)
        sub_lang_list = re.findall(r'name="([^"]*)"[^>]+lang_code="([\w\-]+)"', sub_list)
        sub_lang_list = dict((l[1], l[0]) for l in sub_lang_list)
        if not sub_lang_list:
            return (u'video doesn\'t have subtitles', None)
        return sub_lang_list

    def _list_available_subtitles(self, video_id):
        sub_lang_list = self._get_available_subtitles(video_id)
        self.report_video_subtitles_available(video_id, sub_lang_list)

    def _request_subtitle(self, sub_lang, sub_name, video_id, format):
        """
        Return tuple:
        (error_message, sub_lang, sub)
        """
        self.report_video_subtitles_request(video_id, sub_lang, format)
        params = compat_urllib_parse.urlencode({
            'lang': sub_lang,
            'name': sub_name,
            'v': video_id,
            'fmt': format,
        })
        url = 'http://www.youtube.com/api/timedtext?' + params
        try:
            sub = compat_urllib_request.urlopen(url).read().decode('utf-8')
        except (compat_urllib_error.URLError, compat_http_client.HTTPException, socket.error) as err:
            return (u'unable to download video subtitles: %s' % compat_str(err), None, None)
        if not sub:
            return (u'Did not fetch video subtitles', None, None)
        return (None, sub_lang, sub)

    def _request_automatic_caption(self, video_id, webpage):
        """We need the webpage for getting the captions url, pass it as an
           argument to speed up the process."""
        sub_lang = self._downloader.params.get('subtitleslang') or 'en'
        sub_format = self._downloader.params.get('subtitlesformat')
        self.to_screen(u'%s: Looking for automatic captions' % video_id)
        mobj = re.search(r';ytplayer.config = ({.*?});', webpage)
        err_msg = u'Couldn\'t find automatic captions for "%s"' % sub_lang
        if mobj is None:
            return [(err_msg, None, None)]
        player_config = json.loads(mobj.group(1))
        try:
            args = player_config[u'args']
            caption_url = args[u'ttsurl']
            timestamp = args[u'timestamp']
            params = compat_urllib_parse.urlencode({
                'lang': 'en',
                'tlang': sub_lang,
                'fmt': sub_format,
                'ts': timestamp,
                'kind': 'asr',
            })
            subtitles_url = caption_url + '&' + params
            sub = self._download_webpage(subtitles_url, video_id, u'Downloading automatic captions')
            return [(None, sub_lang, sub)]
        except KeyError:
            return [(err_msg, None, None)]

    def _extract_subtitle(self, video_id):
        """
        Return a list with a tuple:
        [(error_message, sub_lang, sub)]
        """
        sub_lang_list = self._get_available_subtitles(video_id)
        sub_format = self._downloader.params.get('subtitlesformat')
        if  isinstance(sub_lang_list,tuple): #There was some error, it didn't get the available subtitles
            return [(sub_lang_list[0], None, None)]
        if self._downloader.params.get('subtitleslang', False):
            sub_lang = self._downloader.params.get('subtitleslang')
        elif 'en' in sub_lang_list:
            sub_lang = 'en'
        else:
            sub_lang = list(sub_lang_list.keys())[0]
        if not sub_lang in sub_lang_list:
            return [(u'no closed captions found in the specified language "%s"' % sub_lang, None, None)]

        subtitle = self._request_subtitle(sub_lang, sub_lang_list[sub_lang].encode('utf-8'), video_id, sub_format)
        return [subtitle]

    def _extract_all_subtitles(self, video_id):
        sub_lang_list = self._get_available_subtitles(video_id)
        sub_format = self._downloader.params.get('subtitlesformat')
        if  isinstance(sub_lang_list,tuple): #There was some error, it didn't get the available subtitles
            return [(sub_lang_list[0], None, None)]
        subtitles = []
        for sub_lang in sub_lang_list:
            subtitle = self._request_subtitle(sub_lang, sub_lang_list[sub_lang].encode('utf-8'), video_id, sub_format)
            subtitles.append(subtitle)
        return subtitles

    def _print_formats(self, formats):
        print('Available formats:')
        for x in formats:
            print('%s\t:\t%s\t[%s]%s' %(x, self._video_extensions.get(x, 'flv'),
                                        self._video_dimensions.get(x, '???'),
                                        ' ('+self._special_itags[x]+')' if x in self._special_itags else ''))

    def _extract_id(self, url):
        mobj = re.match(self._VALID_URL, url, re.VERBOSE)
        if mobj is None:
            raise ExtractorError(u'Invalid URL: %s' % url)
        video_id = mobj.group(2)
        return video_id

    def _get_video_url_list(self, url_map):
        """
        Transform a dictionary in the format {itag:url} to a list of (itag, url)
        with the requested formats.
        """
        req_format = self._downloader.params.get('format', None)
        format_limit = self._downloader.params.get('format_limit', None)
        available_formats = self._available_formats_prefer_free if self._downloader.params.get('prefer_free_formats', False) else self._available_formats
        if format_limit is not None and format_limit in available_formats:
            format_list = available_formats[available_formats.index(format_limit):]
        else:
            format_list = available_formats
        existing_formats = [x for x in format_list if x in url_map]
        if len(existing_formats) == 0:
            raise ExtractorError(u'no known formats available for video')
        if self._downloader.params.get('listformats', None):
            self._print_formats(existing_formats)
            return
        if req_format is None or req_format == 'best':
            video_url_list = [(existing_formats[0], url_map[existing_formats[0]])] # Best quality
        elif req_format == 'worst':
            video_url_list = [(existing_formats[-1], url_map[existing_formats[-1]])] # worst quality
        elif req_format in ('-1', 'all'):
            video_url_list = [(f, url_map[f]) for f in existing_formats] # All formats
        else:
            # Specific formats. We pick the first in a slash-delimeted sequence.
            # For example, if '1/2/3/4' is requested and '2' and '4' are available, we pick '2'.
            req_formats = req_format.split('/')
            video_url_list = None
            for rf in req_formats:
                if rf in url_map:
                    video_url_list = [(rf, url_map[rf])]
                    break
            if video_url_list is None:
                raise ExtractorError(u'requested format not available')
        return video_url_list

    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, u'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 _real_extract(self, url):
        if re.match(r'(?:https?://)?[^/]+/watch\?feature=[a-z_]+$', url):
            self._downloader.report_warning(u'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  ).')

        # 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 = 'https://www.youtube.com/' + compat_urllib_parse.unquote(mobj.group(1)).lstrip('/')
        video_id = self._extract_id(url)

        # Get video webpage
        self.report_video_webpage_download(video_id)
        url = 'https://www.youtube.com/watch?v=%s&gl=US&hl=en&has_verified=1' % video_id
        request = compat_urllib_request.Request(url)
        try:
            video_webpage_bytes = compat_urllib_request.urlopen(request).read()
        except (compat_urllib_error.URLError, compat_http_client.HTTPException, socket.error) as err:
            raise ExtractorError(u'Unable to download video webpage: %s' % compat_str(err))

        video_webpage = video_webpage_bytes.decode('utf-8', 'ignore')

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

        # Get video info
        self.report_video_info_webpage_download(video_id)
        if re.search(r'player-age-gate-content">', video_webpage) is not None:
            self.report_age_confirmation()
            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
            data = compat_urllib_parse.urlencode({'video_id': video_id,
                                                  'el': 'embedded',
                                                  'gl': 'US',
                                                  'hl': 'en',
                                                  'eurl': 'https://youtube.googleapis.com/v/' + video_id,
                                                  'asv': 3,
                                                  'sts':'1588',
                                                  })
            video_info_url = 'https://www.youtube.com/get_video_info?' + data
            video_info_webpage = self._download_webpage(video_info_url, video_id,
                                    note=False,
                                    errnote='unable to download video info webpage')
            video_info = compat_parse_qs(video_info_webpage)
        else:
            age_gate = False
            for el_type in ['&el=embedded', '&el=detailpage', '&el=vevo', '']:
                video_info_url = ('https://www.youtube.com/get_video_info?&video_id=%s%s&ps=default&eurl=&gl=US&hl=en'
                        % (video_id, el_type))
                video_info_webpage = self._download_webpage(video_info_url, video_id,
                                        note=False,
                                        errnote='unable to download video info webpage')
                video_info = compat_parse_qs(video_info_webpage)
                if 'token' in video_info:
                    break
        if 'token' not in video_info:
            if 'reason' in video_info:
                raise ExtractorError(u'YouTube said: %s' % video_info['reason'][0], expected=True)
            else:
                raise ExtractorError(u'"token" parameter not in video info for unknown reason')

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

        # Start extracting information
        self.report_information_extraction(video_id)

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

        # uploader_id
        video_uploader_id = None
        mobj = re.search(r'<link itemprop="url" href="http://www.youtube.com/(?:user|channel)/([^"]+)">', video_webpage)
        if mobj is not None:
            video_uploader_id = mobj.group(1)
        else:
            self._downloader.report_warning(u'unable to extract uploader nickname')

        # title
        if 'title' not in video_info:
            raise ExtractorError(u'Unable to extract video title')
        video_title = compat_urllib_parse.unquote_plus(video_info['title'][0])

        # 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(u'unable to extract video thumbnail')
            video_thumbnail = ''
        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 = None
        mobj = re.search(r'id="eow-date.*?>(.*?)</span>', video_webpage, re.DOTALL)
        if mobj is not None:
            upload_date = ' '.join(re.sub(r'[/,-]', r' ', mobj.group(1)).split())
            upload_date = unified_strdate(upload_date)

        # description
        video_description = get_element_by_id("eow-description", video_webpage)
        if 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 = u''

        # subtitles
        video_subtitles = None

        if self._downloader.params.get('writesubtitles', False):
            video_subtitles = self._extract_subtitle(video_id)
            if video_subtitles:
                (sub_error, sub_lang, sub) = video_subtitles[0]
                if sub_error:
                    self._downloader.report_warning(sub_error)
        
        if self._downloader.params.get('writeautomaticsub', False):
            video_subtitles = self._request_automatic_caption(video_id, video_webpage)
            (sub_error, sub_lang, sub) = video_subtitles[0]
            if sub_error:
                self._downloader.report_warning(sub_error)

        if self._downloader.params.get('allsubtitles', False):
            video_subtitles = self._extract_all_subtitles(video_id)
            for video_subtitle in video_subtitles:
                (sub_error, sub_lang, sub) = video_subtitle
                if sub_error:
                    self._downloader.report_warning(sub_error)

        if self._downloader.params.get('listsubtitles', False):
            self._list_available_subtitles(video_id)
            return

        if 'length_seconds' not in video_info:
            self._downloader.report_warning(u'unable to extract video duration')
            video_duration = ''
        else:
            video_duration = compat_urllib_parse.unquote_plus(video_info['length_seconds'][0])

        # Decide which formats to download

        try:
            mobj = re.search(r';ytplayer.config = ({.*?});', video_webpage)
            if not mobj:
                raise ValueError('Could not find vevo ID')
            info = json.loads(mobj.group(1))
            args = info['args']
            # Easy way to know if the 's' value is in url_encoded_fmt_stream_map
            # this signatures are encrypted
            m_s = re.search(r'[&,]s=', args['url_encoded_fmt_stream_map'])
            if m_s is not None:
                self.to_screen(u'%s: Encrypted signatures detected.' % video_id)
                video_info['url_encoded_fmt_stream_map'] = [args['url_encoded_fmt_stream_map']]
            m_s = re.search(r'[&,]s=', args.get('adaptive_fmts', u''))
            if m_s is not None:
                if 'url_encoded_fmt_stream_map' in video_info:
                    video_info['url_encoded_fmt_stream_map'][0] += ',' + args['adaptive_fmts']
                else:
                    video_info['url_encoded_fmt_stream_map'] = [args['adaptive_fmts']]
            elif 'adaptive_fmts' in video_info:
                if 'url_encoded_fmt_stream_map' in video_info:
                    video_info['url_encoded_fmt_stream_map'][0] += ',' + video_info['adaptive_fmts'][0]
                else:
                    video_info['url_encoded_fmt_stream_map'] = video_info['adaptive_fmts']
        except ValueError:
            pass

        if 'conn' in video_info and video_info['conn'][0].startswith('rtmp'):
            self.report_rtmp_download()
            video_url_list = [(None, video_info['conn'][0])]
        elif 'url_encoded_fmt_stream_map' in video_info and len(video_info['url_encoded_fmt_stream_map']) >= 1:
            if 'rtmpe%3Dyes' in video_info['url_encoded_fmt_stream_map'][0]:
                raise ExtractorError('rtmpe downloads are not supported, see https://github.com/rg3/youtube-dl/issues/343 for more information.', expected=True)
            url_map = {}
            for url_data_str in video_info['url_encoded_fmt_stream_map'][0].split(','):
                url_data = compat_parse_qs(url_data_str)
                if 'itag' in url_data and 'url' in url_data:
                    url = url_data['url'][0]
                    if 'sig' in url_data:
                        url += '&signature=' + url_data['sig'][0]
                    elif 's' in url_data:
                        if self._downloader.params.get('verbose'):
                            s = url_data['s'][0]
                            if age_gate:
                                player_version = self._search_regex(r'ad3-(.+?)\.swf',
                                    video_info['ad3_module'][0] if 'ad3_module' in video_info else 'NOT FOUND',
                                    'flash player', fatal=False)
                                player = 'flash player %s' % player_version
                            else:
                                player = u'html5 player %s' % self._search_regex(r'html5player-(.+?)\.js', video_webpage,
                                    'html5 player', fatal=False)
                            parts_sizes = u'.'.join(compat_str(len(part)) for part in s.split('.'))
                            self.to_screen(u'encrypted signature length %d (%s), itag %s, %s' %
                                (len(s), parts_sizes, url_data['itag'][0], player))
                        encrypted_sig = url_data['s'][0]
                        if age_gate:
                            signature = self._decrypt_signature_age_gate(encrypted_sig)
                        else:
                            signature = self._decrypt_signature(encrypted_sig)
                        url += '&signature=' + signature
                    if 'ratebypass' not in url:
                        url += '&ratebypass=yes'
                    url_map[url_data['itag'][0]] = url
            video_url_list = self._get_video_url_list(url_map)
            if not video_url_list:
                return
        elif video_info.get('hlsvp'):
            manifest_url = video_info['hlsvp'][0]
            url_map = self._extract_from_m3u8(manifest_url, video_id)
            video_url_list = self._get_video_url_list(url_map)
            if not video_url_list:
                return

        else:
            raise ExtractorError(u'no conn or url_encoded_fmt_stream_map information found in video info')

        results = []
        for format_param, video_real_url in video_url_list:
            # Extension
            video_extension = self._video_extensions.get(format_param, 'flv')

            video_format = '{0} - {1}{2}'.format(format_param if format_param else video_extension,
                                              self._video_dimensions.get(format_param, '???'),
                                              ' ('+self._special_itags[format_param]+')' if format_param in self._special_itags else '')

            results.append({
                'id':       video_id,
                'url':      video_real_url,
                'uploader': video_uploader,
                'uploader_id': video_uploader_id,
                'upload_date':  upload_date,
                'title':    video_title,
                'ext':      video_extension,
                'format':   video_format,
                'thumbnail':    video_thumbnail,
                'description':  video_description,
                'player_url':   player_url,
                'subtitles':    video_subtitles,
                'duration':     video_duration
            })
        return results

class YoutubePlaylistIE(InfoExtractor):
    IE_DESC = u'YouTube.com playlists'
    _VALID_URL = r"""(?:
                        (?:https?://)?
                        (?:\w+\.)?
                        youtube\.com/
                        (?:
                           (?:course|view_play_list|my_playlists|artist|playlist|watch)
                           \? (?:.*?&)*? (?:p|a|list)=
                        |  p/
                        )
                        ((?:PL|EC|UU|FL)?[0-9A-Za-z-_]{10,})
                        .*
                     |
                        ((?:PL|EC|UU|FL)[0-9A-Za-z-_]{10,})
                     )"""
    _TEMPLATE_URL = 'https://gdata.youtube.com/feeds/api/playlists/%s?max-results=%i&start-index=%i&v=2&alt=json&safeSearch=none'
    _MAX_RESULTS = 50
    IE_NAME = u'youtube:playlist'

    @classmethod
    def suitable(cls, url):
        """Receives a URL and returns True if suitable for this IE."""
        return re.match(cls._VALID_URL, url, re.VERBOSE) is not None

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

        # Download playlist videos from API
        playlist_id = mobj.group(1) or mobj.group(2)
        videos = []

        for page_num in itertools.count(1):
            start_index = self._MAX_RESULTS * (page_num - 1) + 1
            if start_index >= 1000:
                self._downloader.report_warning(u'Max number of results reached')
                break
            url = self._TEMPLATE_URL % (playlist_id, self._MAX_RESULTS, start_index)
            page = self._download_webpage(url, playlist_id, u'Downloading page #%s' % page_num)

            try:
                response = json.loads(page)
            except ValueError as err:
                raise ExtractorError(u'Invalid JSON in API response: ' + compat_str(err))

            if 'feed' not in response:
                raise ExtractorError(u'Got a malformed response from YouTube API')
            playlist_title = response['feed']['title']['$t']
            if 'entry' not in response['feed']:
                # Number of videos is a multiple of self._MAX_RESULTS
                break

            for entry in response['feed']['entry']:
                index = entry['yt$position']['$t']
                if 'media$group' in entry and 'media$player' in entry['media$group']:
                    videos.append((index, entry['media$group']['media$player']['url']))

        videos = [v[1] for v in sorted(videos)]

        url_results = [self.url_result(vurl, 'Youtube') for vurl in videos]
        return [self.playlist_result(url_results, playlist_id, playlist_title)]


class YoutubeChannelIE(InfoExtractor):
    IE_DESC = u'YouTube.com channels'
    _VALID_URL = r"^(?:https?://)?(?:youtu\.be|(?:\w+\.)?youtube(?:-nocookie)?\.com)/channel/([0-9A-Za-z_-]+)"
    _TEMPLATE_URL = 'http://www.youtube.com/channel/%s/videos?sort=da&flow=list&view=0&page=%s&gl=US&hl=en'
    _MORE_PAGES_INDICATOR = 'yt-uix-load-more'
    _MORE_PAGES_URL = 'http://www.youtube.com/c4_browse_ajax?action_load_more_videos=1&flow=list&paging=%s&view=0&sort=da&channel_id=%s'
    IE_NAME = u'youtube:channel'

    def extract_videos_from_page(self, page):
        ids_in_page = []
        for mobj in re.finditer(r'href="/watch\?v=([0-9A-Za-z_-]+)&?', page):
            if mobj.group(1) not in ids_in_page:
                ids_in_page.append(mobj.group(1))
        return ids_in_page

    def _real_extract(self, url):
        # Extract channel id
        mobj = re.match(self._VALID_URL, url)
        if mobj is None:
            raise ExtractorError(u'Invalid URL: %s' % url)

        # Download channel page
        channel_id = mobj.group(1)
        video_ids = []
        pagenum = 1

        url = self._TEMPLATE_URL % (channel_id, pagenum)
        page = self._download_webpage(url, channel_id,
                                      u'Downloading page #%s' % pagenum)

        # Extract video identifiers
        ids_in_page = self.extract_videos_from_page(page)
        video_ids.extend(ids_in_page)

        # Download any subsequent channel pages using the json-based channel_ajax query
        if self._MORE_PAGES_INDICATOR in page:
            for pagenum in itertools.count(1):
                url = self._MORE_PAGES_URL % (pagenum, channel_id)
                page = self._download_webpage(url, channel_id,
                                              u'Downloading page #%s' % pagenum)

                page = json.loads(page)

                ids_in_page = self.extract_videos_from_page(page['content_html'])
                video_ids.extend(ids_in_page)

                if self._MORE_PAGES_INDICATOR  not in page['load_more_widget_html']:
                    break

        self._downloader.to_screen(u'[youtube] Channel %s: Found %i videos' % (channel_id, len(video_ids)))

        urls = ['http://www.youtube.com/watch?v=%s' % id for id in video_ids]
        url_entries = [self.url_result(eurl, 'Youtube') for eurl in urls]
        return [self.playlist_result(url_entries, channel_id)]


class YoutubeUserIE(InfoExtractor):
    IE_DESC = u'YouTube.com user videos (URL or "ytuser" keyword)'
    _VALID_URL = r'(?:(?:(?:https?://)?(?:\w+\.)?youtube\.com/user/)|ytuser:)([A-Za-z0-9_-]+)'
    _TEMPLATE_URL = 'http://gdata.youtube.com/feeds/api/users/%s'
    _GDATA_PAGE_SIZE = 50
    _GDATA_URL = 'http://gdata.youtube.com/feeds/api/users/%s/uploads?max-results=%d&start-index=%d'
    _VIDEO_INDICATOR = r'/watch\?v=(.+?)[\<&]'
    IE_NAME = u'youtube:user'

    def _real_extract(self, url):
        # Extract username
        mobj = re.match(self._VALID_URL, url)
        if mobj is None:
            raise ExtractorError(u'Invalid URL: %s' % url)

        username = mobj.group(1)

        # Download video ids using YouTube Data API. Result size per
        # query is limited (currently to 50 videos) so we need to query
        # page by page until there are no video ids - it means we got
        # all of them.

        video_ids = []

        for pagenum in itertools.count(0):
            start_index = pagenum * self._GDATA_PAGE_SIZE + 1

            gdata_url = self._GDATA_URL % (username, self._GDATA_PAGE_SIZE, start_index)
            page = self._download_webpage(gdata_url, username,
                                          u'Downloading video ids from %d to %d' % (start_index, start_index + self._GDATA_PAGE_SIZE))

            # Extract video identifiers
            ids_in_page = []

            for mobj in re.finditer(self._VIDEO_INDICATOR, page):
                if mobj.group(1) not in ids_in_page:
                    ids_in_page.append(mobj.group(1))

            video_ids.extend(ids_in_page)

            # A little optimization - if current page is not
            # "full", ie. does not contain PAGE_SIZE video ids then
            # we can assume that this page is the last one - there
            # are no more ids on further pages - no need to query
            # again.

            if len(ids_in_page) < self._GDATA_PAGE_SIZE:
                break

        urls = ['http://www.youtube.com/watch?v=%s' % video_id for video_id in video_ids]
        url_results = [self.url_result(rurl, 'Youtube') for rurl in urls]
        return [self.playlist_result(url_results, playlist_title = username)]

class YoutubeSearchIE(SearchInfoExtractor):
    IE_DESC = u'YouTube.com searches'
    _API_URL = 'https://gdata.youtube.com/feeds/api/videos?q=%s&start-index=%i&max-results=50&v=2&alt=jsonc'
    _MAX_RESULTS = 1000
    IE_NAME = u'youtube:search'
    _SEARCH_KEY = 'ytsearch'

    def report_download_page(self, query, pagenum):
        """Report attempt to download search page with given number."""
        self._downloader.to_screen(u'[youtube] query "%s": Downloading page %s' % (query, pagenum))

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

        video_ids = []
        pagenum = 0
        limit = n

        while (50 * pagenum) < limit:
            self.report_download_page(query, pagenum+1)
            result_url = self._API_URL % (compat_urllib_parse.quote_plus(query), (50*pagenum)+1)
            request = compat_urllib_request.Request(result_url)
            try:
                data = compat_urllib_request.urlopen(request).read().decode('utf-8')
            except (compat_urllib_error.URLError, compat_http_client.HTTPException, socket.error) as err:
                raise ExtractorError(u'Unable to download API page: %s' % compat_str(err))
            api_response = json.loads(data)['data']

            if not 'items' in api_response:
                raise ExtractorError(u'[youtube] No video results')

            new_ids = list(video['id'] for video in api_response['items'])
            video_ids += new_ids

            limit = min(n, api_response['totalItems'])
            pagenum += 1

        if len(video_ids) > n:
            video_ids = video_ids[:n]
        videos = [self.url_result('http://www.youtube.com/watch?v=%s' % id, 'Youtube') for id in video_ids]
        return self.playlist_result(videos, query)


class YoutubeShowIE(InfoExtractor):
    IE_DESC = u'YouTube.com (multi-season) shows'
    _VALID_URL = r'https?://www\.youtube\.com/show/(.*)'
    IE_NAME = u'youtube:show'

    def _real_extract(self, url):
        mobj = re.match(self._VALID_URL, url)
        show_name = mobj.group(1)
        webpage = self._download_webpage(url, show_name, u'Downloading show webpage')
        # There's one playlist for each season of the show
        m_seasons = list(re.finditer(r'href="(/playlist\?list=.*?)"', webpage))
        self.to_screen(u'%s: Found %s seasons' % (show_name, len(m_seasons)))
        return [self.url_result('https://www.youtube.com' + season.group(1), 'YoutubePlaylist') for season in m_seasons]


class YoutubeFeedsInfoExtractor(YoutubeBaseInfoExtractor):
    """
    Base class for extractors that fetch info from
    http://www.youtube.com/feed_ajax
    Subclasses must define the _FEED_NAME and _PLAYLIST_TITLE properties.
    """
    _LOGIN_REQUIRED = True
    _PAGING_STEP = 30
    # use action_load_personal_feed instead of action_load_system_feed
    _PERSONAL_FEED = False

    @property
    def _FEED_TEMPLATE(self):
        action = 'action_load_system_feed'
        if self._PERSONAL_FEED:
            action = 'action_load_personal_feed'
        return 'http://www.youtube.com/feed_ajax?%s=1&feed_name=%s&paging=%%s' % (action, self._FEED_NAME)

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

    def _real_initialize(self):
        self._login()

    def _real_extract(self, url):
        feed_entries = []
        # The step argument is available only in 2.7 or higher
        for i in itertools.count(0):
            paging = i*self._PAGING_STEP
            info = self._download_webpage(self._FEED_TEMPLATE % paging,
                                          u'%s feed' % self._FEED_NAME,
                                          u'Downloading page %s' % i)
            info = json.loads(info)
            feed_html = info['feed_html']
            m_ids = re.finditer(r'"/watch\?v=(.*?)["&]', feed_html)
            ids = orderedSet(m.group(1) for m in m_ids)
            feed_entries.extend(self.url_result(id, 'Youtube') for id in ids)
            if info['paging'] is None:
                break
        return self.playlist_result(feed_entries, playlist_title=self._PLAYLIST_TITLE)

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

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

class YoutubeWatchLaterIE(YoutubeFeedsInfoExtractor):
    IE_DESC = u'Youtube watch later list, "ytwatchlater" keyword (requires authentication)'
    _VALID_URL = r'https?://www\.youtube\.com/feed/watch_later|:ytwatchlater'
    _FEED_NAME = 'watch_later'
    _PLAYLIST_TITLE = u'Youtube Watch Later'
    _PAGING_STEP = 100
    _PERSONAL_FEED = True

class YoutubeFavouritesIE(YoutubeBaseInfoExtractor):
    IE_NAME = u'youtube:favorites'
    IE_DESC = u'YouTube.com favourite videos, "ytfav" keyword (requires authentication)'
    _VALID_URL = r'https?://www\.youtube\.com/my_favorites|:ytfav(?:o?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, u'favourites playlist id')
        return self.url_result(playlist_id, 'YoutubePlaylist')