Description:

Features
- 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, single importable module file (pafy.py)
- Select highest quality stream for download or streaming
- Download video only (no audio) in m4v or webm format
- Download audio only (no video) in ogg or m4a format
- Retrieve playlists and playlist metadata
- Works with Python 2.6+ and 3.3+
- Optionally depends on youtube-dl (recommended; more stable)