[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/downloader/f4m.py

@@ -220,6 +220,7 @@ class F4mFD(FileDownloader):
 
     def real_download(self, filename, info_dict):
         man_url = info_dict['url']
+        requested_bitrate = info_dict.get('tbr')
         self.to_screen('[download] Downloading f4m manifest')
         manifest = self.ydl.urlopen(man_url).read()
         self.report_destination(filename)
@@ -233,8 +234,14 @@ def real_download(self, filename, info_dict):
 
         doc = etree.fromstring(manifest)
         formats = [(int(f.attrib.get('bitrate', -1)), f) for f in doc.findall(_add_ns('media'))]
-        formats = sorted(formats, key=lambda f: f[0])
-        rate, media = formats[-1]
+        if requested_bitrate is None:
+            # get the best format
+            formats = sorted(formats, key=lambda f: f[0])
+            rate, media = formats[-1]
+        else:
+            rate, media = list(filter(
+                lambda f: int(f[0]) == requested_bitrate, formats))[0]
+
         base_url = compat_urlparse.urljoin(man_url, media.attrib['url'])
         bootstrap = base64.b64decode(doc.find(_add_ns('bootstrapInfo')).text)
         metadata = base64.b64decode(media.find(_add_ns('metadata')).text)

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 @@ def _real_extract(self, url):
         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 @@
     clean_html,
     compiled_regex_type,
     ExtractorError,
+    int_or_none,
     RegexNotFoundError,
     sanitize_filename,
     unescapeHTML,
@@ -590,6 +591,22 @@ def _sleep(self, timeout, video_id, msg_template=None):
         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):
     """