Download videos and retrieve metadata from YouTube. This python library can retrieve metadata such as
viewcount, duration, rating, author, thumbnail, keywords, download video or audio at requested resolution
/ bitrate / format / filesize, command line tool (ytdl) for downloading directly from the command line,
retrieve the URL to stream the video in a player such as vlc or mplayer, works with age-restricted videos
and non-embeddable videos, small, standalone, select highest quality stream for download or streaming,
download audio only (no video) in ogg or m4a format, download video only (no audio) in m4v format.