Merge branch 'subtitles-rework'

(Closes PR #4964)

youtube_dl/extractor/common.py

@@ -150,8 +150,14 @@ class InfoExtractor(object):
                     If not explicitly set, calculated from timestamp.
     uploader_id:    Nickname or id of the video uploader.
     location:       Physical location where the video was filmed.
-    subtitles:      The subtitle file contents as a dictionary in the format
-                    {language: subtitles}.
+    subtitles:      The available subtitles as a dictionary in the format
+                    {language: subformats}. "subformats" is a list sorted from
+                    lower to higher preference, each element is a dictionary
+                    with the "ext" entry and one of:
+                        * "data": The subtitles file contents
+                        * "url": A url pointing to the subtitles file
+    automatic_captions: Like 'subtitles', used by the YoutubeIE for
+                    automatically generated captions
     duration:       Length of the video in seconds, as an integer.
     view_count:     How many users have watched the video on the platform.
     like_count:     Number of positive ratings of the video
@@ -1011,6 +1017,24 @@ class InfoExtractor(object):
             any_restricted = any_restricted or is_restricted
         return not any_restricted
 
+    def extract_subtitles(self, *args, **kwargs):
+        if (self._downloader.params.get('writesubtitles', False) or
+                self._downloader.params.get('listsubtitles')):
+            return self._get_subtitles(*args, **kwargs)
+        return {}
+
+    def _get_subtitles(self, *args, **kwargs):
+        raise NotImplementedError("This method must be implemented by subclasses")
+
+    def extract_automatic_captions(self, *args, **kwargs):
+        if (self._downloader.params.get('writeautomaticsub', False) or
+                self._downloader.params.get('listsubtitles')):
+            return self._get_automatic_captions(*args, **kwargs)
+        return {}
+
+    def _get_automatic_captions(self, *args, **kwargs):
+        raise NotImplementedError("This method must be implemented by subclasses")
+
 
 class SearchInfoExtractor(InfoExtractor):
     """