[Coub] Fix media format identification (#1469)

Authored by: wlritchi

yt_dlp/extractor/coub.py

@@ -57,7 +57,7 @@ class CoubIE(InfoExtractor):
 
         file_versions = coub['file_versions']
 
-        QUALITIES = ('low', 'med', 'high')
+        QUALITIES = ('low', 'med', 'high', 'higher')
 
         MOBILE = 'mobile'
         IPHONE = 'iphone'
@@ -86,6 +86,7 @@ class CoubIE(InfoExtractor):
                     'format_id': '%s-%s-%s' % (HTML5, kind, quality),
                     'filesize': int_or_none(item.get('size')),
                     'vcodec': 'none' if kind == 'audio' else None,
+                    'acodec': 'none' if kind == 'video' else None,
                     'quality': quality_key(quality),
                     'source_preference': preference_key(HTML5),
                 })