[bloomberg] Extract the available formats (closes #2776)

It uses a helper method in the InfoExtractor class.
The downloader will pick the requested formats using the bitrate in the info dict.

youtube_dl/extractor/bloomberg.py

@@ -10,7 +10,7 @@ class BloombergIE(InfoExtractor):
 
     _TEST = {
         'url': 'http://www.bloomberg.com/video/shah-s-presentation-on-foreign-exchange-strategies-qurhIVlJSB6hzkVi229d8g.html',
-        'md5': '7bf08858ff7c203c870e8a6190e221e5',
+        # The md5 checksum changes
         'info_dict': {
             'id': 'qurhIVlJSB6hzkVi229d8g',
             'ext': 'flv',
@@ -31,8 +31,7 @@ class BloombergIE(InfoExtractor):
         return {
             'id': name.split('-')[-1],
             'title': title,
-            'url': f4m_url,
-            'ext': 'flv',
+            'formats': self._extract_f4m_formats(f4m_url, name),
             'description': self._og_search_description(webpage),
             'thumbnail': self._og_search_thumbnail(webpage),
         }

youtube_dl/extractor/common.py

@@ -18,6 +18,7 @@ from ..utils import (
     clean_html,
     compiled_regex_type,
     ExtractorError,
+    int_or_none,
     RegexNotFoundError,
     sanitize_filename,
     unescapeHTML,
@@ -590,6 +591,22 @@ class InfoExtractor(object):
         self.to_screen(msg)
         time.sleep(timeout)
 
+    def _extract_f4m_formats(self, manifest_url, video_id):
+        manifest = self._download_xml(manifest_url, video_id)
+
+        formats = []
+        for media_el in manifest.findall('{http://ns.adobe.com/f4m/1.0}media'):
+            formats.append({
+                'url': manifest_url,
+                'ext': 'flv',
+                'tbr': int_or_none(media_el.attrib.get('bitrate')),
+                'width': int_or_none(media_el.attrib.get('width')),
+                'height': int_or_none(media_el.attrib.get('height')),
+            })
+        self._sort_formats(formats)
+
+        return formats
+
 
 class SearchInfoExtractor(InfoExtractor):
     """