gistfile1.py

from urllib.parse import urlparse, parse_qs
from django.utils.translation import ugettext_lazy as _
from django.db import models
from django import  forms
import re
 
def validate_youtube_url(value):
    """
    El patron lo saque de http://stackoverflow.com/questions/2964678/jquery-youtube-url-validation-with-regex
    """
    pattern = r'^http(?:s)?:\/\/(?:www\.)?youtube.com\/watch\?(?=.*v=\w+)(?:\S+)?$'
 
    if value[:16] == 'http://youtu.be/':
        if re.match(r'\w+', value[16:]) is None:
            raise forms.ValidationError(_('Not a valid Youtube URL'))
    elif re.match(pattern, value) is None:
        raise forms.ValidationError(_('Not a valid Youtube URL'))
 
 
class YoutubeUrl(str):
    @property
    def video_id(self):
        parsed_url = urlparse(self)
        if parsed_url.query == '':
            return parsed_url.path
        return parse_qs(parsed_url.query)['v'][0]
 
    @property
    def embed_url(self):
        return 'http://youtube.com/embed/%s/' % self.video_id
 
    @property
    def thumb(self):
        return "http://img.youtube.com/vi/%s/2.jpg" % self.video_id
 
class YoutubeUrlField(models.URLField, metaclass=models.SubfieldBase):
 
    def __init__(self, *args, **kwargs):
        super(YoutubeUrlField, self).__init__(*args, **kwargs)
        self.validators.append(validate_youtube_url)
 
    def to_python(self, value): 
        url = super(YoutubeUrlField, self).to_python(value) 
        return YoutubeUrl(url)
 
    def get_prep_value(self, value):
        return str(value)

Forked and updated to work with python3, and https video