youtube_bisiler.py

import pafy
import re

_slugify_strip_re = re.compile(r'[^\w\s-]')
_slugify_hyphenate_re = re.compile(r'[-\s]+')
def _slugify(value):
    """
        Normalizes string, converts to lowercase, removes non-alpha characters,
        and converts spaces to hyphens.
        
        From Django's "django/template/defaultfilters.py".
        """
    import unicodedata
    if not isinstance(value, unicode):
        value = unicode(value)
    value = unicodedata.normalize('NFKD', value).encode('ascii', 'ignore')
    value = unicode(_slugify_strip_re.sub('', value).strip().lower())
    return _slugify_hyphenate_re.sub('-', value)

url = "https://www.youtube.com/watch?v=_FE194VN6c4"
video = pafy.new(url)

print video.title
streams = video.streams
print "Available video streams :"
for s in streams:
    print(s.resolution, s.extension)

print "Available audio streams :"
audiostreams = video.audiostreams
for a in audiostreams:
    print(a.bitrate, a.extension, a.get_filesize())


bestaudio = video.getbestaudio()
filename = _slugify(video.title) +"."+ bestaudio.extension
print filename
bestaudio.download(quiet=False,filepath=filename)