The following fields are optional:
+ display_id An alternative identifier for the video, not necessarily
+ unique, but available before title. Typically, id is
+ something like "4234987", title "Dancing naked mole rats",
+ and display_id "dancing-naked-mole-rats"
thumbnails: A list of dictionaries (with the entries "resolution" and
"url") for the varying thumbnails
thumbnail: Full URL to a video thumbnail image.