Move JWPlayer JSON array handling to IQM2

Out of @yan12125's concern that the presumption that JWPlayer data as
an array representing multiple formats rather than a playlist might be
specific to IQM2, move this code from jwplatform.py to iqm2.py.

JWPlatformBase now reverts to throwing a TypeError if it gets an
array.

Now IQM2 redefines the _extract_jwplayer_data() method as well, but it
continues to leverage JWPlatformBase for _parse_jwplayer_data(), which
is the bulk of the work.

youtube_dl/extractor/iqm2.py

@@ -1,12 +1,12 @@
 # coding: utf-8
 from __future__ import unicode_literals
-from ..utils import smuggle_url
 
 import re
 
 from .common import InfoExtractor
 from ..compat import compat_urlparse
 from .jwplatform import JWPlatformBaseIE
+from ..utils import js_to_json
 
 # IQM2 aka Accela is a municipal meeting management platform that
 # (among other things) stores livestreamed video from municipal
@@ -63,6 +63,18 @@ class IQM2IE(JWPlatformBaseIE):
         if mobj:
             return mobj.group('options')
         
+    def _extract_jwplayer_data(self, webpage, video_id, *args, **kwargs):
+        jwplayer_data = self._parse_json(
+            self._find_jwplayer_data(webpage), video_id,
+            transform_source=js_to_json)
+
+        assert(isinstance(jwplayer_data, list))
+        jwplayer_data = {'sources': jwplayer_data }
+        jwplayer_data['tracks'] = jwplayer_data['sources'][0].get('tracks')
+        
+        return self._parse_jwplayer_data(
+            jwplayer_data, video_id, *args, **kwargs)
+
     def _real_extract(self, url):
         parent_id = self._match_id(url)
         webpage = self._download_webpage(url, parent_id)

youtube_dl/extractor/jwplatform.py

@@ -50,10 +50,6 @@ class JWPlatformBaseIE(InfoExtractor):
             # JWPlayer backward compatibility: flattened sources
             # https://github.com/jwplayer/jwplayer/blob/v7.4.3/src/js/playlist/item.js#L29-L35
             if 'sources' not in video_data:
-                if isinstance(video_data, list):
-                    video_data = {'sources': video_data }
-                    video_data['tracks'] = video_data['sources'][0].get('tracks')
-                else:
                 video_data['sources'] = [video_data]
 
             this_video_id = video_id or video_data['mediaid']