[youtube] Support automatic captions with original language different from English...
[youtube-dl] / youtube_dl / extractor / subtitles.py
1 from .common import InfoExtractor
2
3 from ..utils import (
4     compat_str,
5     ExtractorError,
6 )
7
8
9 class SubtitlesInfoExtractor(InfoExtractor):
10
11     def _list_available_subtitles(self, video_id):
12         """ outputs the available subtitles for the video """
13         sub_lang_list = self._get_available_subtitles(video_id)
14         sub_lang = ",".join(list(sub_lang_list.keys()))
15         self.to_screen(u'%s: Available subtitles for video: %s' %
16                        (video_id, sub_lang))
17
18     def extract_subtitles(self, video_id, video_webpage=None):
19         """ returns {sub_lang: sub} or {} if subtitles not found """
20         if self._downloader.params.get('writesubtitles', False) or self._downloader.params.get('allsubtitles', False):
21             available_subs_list = self._get_available_subtitles(video_id)
22         elif self._downloader.params.get('writeautomaticsub', False):
23             available_subs_list = self._get_available_automatic_caption(video_id, video_webpage)
24         else:
25             return None
26
27         if not available_subs_list:  # error, it didn't get the available subtitles
28             return {}
29         if self._downloader.params.get('allsubtitles', False):
30             sub_lang_list = available_subs_list
31         else:
32             if self._downloader.params.get('subtitleslangs', False):
33                 requested_langs = self._downloader.params.get('subtitleslangs')
34             elif 'en' in available_subs_list:
35                 requested_langs = ['en']
36             else:
37                 requested_langs = [list(available_subs_list.keys())[0]]
38
39             sub_lang_list = {}
40             for sub_lang in requested_langs:
41                 if not sub_lang in available_subs_list:
42                     self._downloader.report_warning(u'no closed captions found in the specified language "%s"' % sub_lang)
43                     continue
44                 sub_lang_list[sub_lang] = available_subs_list[sub_lang]
45
46         subtitles = {}
47         for sub_lang, url in sub_lang_list.items():
48             subtitle = self._request_subtitle_url(sub_lang, url)
49             if subtitle:
50                 subtitles[sub_lang] = subtitle
51         return subtitles
52
53     def _request_subtitle_url(self, sub_lang, url):
54         """ makes the http request for the subtitle """
55         try:
56             sub = self._download_webpage(url, None, note=False)
57         except ExtractorError as err:
58             self._downloader.report_warning(u'unable to download video subtitles for %s: %s' % (sub_lang, compat_str(err)))
59             return
60         if not sub:
61             self._downloader.report_warning(u'Did not fetch video subtitles')
62             return
63         return sub
64
65     def _get_available_subtitles(self, video_id):
66         """
67         returns {sub_lang: url} or {} if not available
68         Must be redefined by the subclasses
69         """
70         pass
71
72     def _get_available_automatic_caption(self, video_id, webpage):
73         """
74         returns {sub_lang: url} or {} if not available
75         Must be redefined by the subclasses that support automatic captions,
76         otherwise it will return {}
77         """
78         self._downloader.report_warning(u'Automatic Captions not supported by this server')
79         return {}