[extractor/common] Introduce music album metafields

diff --git a/youtube_dl/extractor/common.py b/youtube_dl/extractor/common.py
index ec6625eeae337ccc2925d8e70f4130f465e0b386..2b40f3b7c70e2440401ca73f95fe733f74301cae 100644 (file)
--- a/youtube_dl/extractor/common.py
+++ b/youtube_dl/extractor/common.py
@@ -232,6 +232,24 @@ class InfoExtractor(object):
     episode_number: Number of the video episode within a season, as an integer.
     episode_id:     Id of the video episode, as a unicode string.
 
     episode_number: Number of the video episode within a season, as an integer.
     episode_id:     Id of the video episode, as a unicode string.
 

+    The following fields should only be used when the media is a track or a part of
+    a music album:
+
+    track:          Title of the track.
+    track_number:   Number of the track within an album or a disc, as an integer.
+    track_id:       Id of the track (useful in case of custom indexing, e.g. 6.iii),
+                    as a unicode string.
+    artist:         Artist(s) of the track.
+    genre:          Genre(s) of the track.
+    album:          Title of the album the track belongs to.
+    album_type:     Type of the album (e.g. "Demo", "Full-length", "Split", "Compilation", etc).
+    album_artist:   List of all artists appeared on the album (e.g.
+                    "Ash Borer / Fell Voices" or "Various Artists", useful for splits
+                    and compilations).
+    disc_number:    Number of the disc or other physical medium the track belongs to,
+                    as an integer.
+    release_year:   Year (YYYY) when the album was released.
+

     Unless mentioned otherwise, the fields should be Unicode strings.
 
     Unless mentioned otherwise, None is equivalent to absence of information.
     Unless mentioned otherwise, the fields should be Unicode strings.
 
     Unless mentioned otherwise, None is equivalent to absence of information.