you-get是github上python的一个开源库(https://github.com/soimort/you-get)，使用you-get你只需要取得视频所在网页链接地址就可以很轻松的下载下来，目前you-get所支持的网站包含国内外几十个网站(youtube、twitter、腾讯、爱奇艺、优酷、bilibili等)，基本上可以满足你的需求。

1.you-get可以直接通过命令行使用（前提是你要先安装you-get：pip install you-get）

下载命令：you-get your-url

l例如：you-get https://www.bilibili.com/bangumi/play/ep118488from=search&seid=5050973611974373611

效果如下：（我直接在pycharm的终端命令行执行）

2.通过python 简单调用you-get库

# ！/usr/bin/env python
# -*-coding:utf-8-*-
"""
@Author : xiaofeng
@Time  : 2018/12/25 10:26
@Desc : Less interests,More interest.
@Project : python_appliction
@FileName: you-get.py
@Software: PyCharm
@Blog  ：https://blog.csdn.net/zwx19921215
"""
import sys
import you_get


def download(url, path):
    sys.argv = ['you-get', '-o', path, url]
    you_get.main()


if __name__ == '__main__':
    # 视频网站的地址
    url = 'https://www.bilibili.com/bangumi/play/ep118488from=search&seid=5050973611974373611'
    # 视频输出的位置
    path = 'G:/test'
    download(url, path)

3.python 简单集成 tkinter，通过GUI的形式展现（单线程，未做优化，后续做优化处理）

# ！/usr/bin/env python
# -*-coding:utf-8-*-
"""
@Author : xiaofeng
@Time  : 2018/12/25 11:50
@Desc : Less interests,More interest.
@Project : python_appliction
@FileName: you-get2.py
@Software: PyCharm
@Blog  ：https://blog.csdn.net/zwx19921215
"""

import re
import sys
import tkinter as tk
import tkinter.messagebox as msgbox
import webbrowser

import you_get

"""
视频下载类
"""


class DownloadApp:
    # construct
    def __init__(self, width=800, height=200):
        self.w = width
        self.h = height
        self.title = '视频下载助手'
        self.root = tk.Tk(className=self.title)
        self.url = tk.StringVar()
        self.start = tk.IntVar()
        self.end = tk.IntVar()
        self.path = tk.StringVar()
        self.path.set('D:/DownloadApp')

        # define frame
        frame_1 = tk.Frame(self.root)
        frame_2 = tk.Frame(self.root)
        frame_3 = tk.Frame(self.root)
        frame_4 = tk.Frame(self.root)

        # menu
        menu = tk.Menu(self.root)
        self.root.config(menu=menu)
        menu1 = tk.Menu(menu, tearoff=0)
        menu.add_cascade(label='Menu', menu=menu1)
        menu1.add_command(label='about me', command=lambda: webbrowser.open('https://blog.csdn.net/zwx19921215'))
        menu1.add_command(label='exit', command=lambda: self.root.quit())

        # set frame_1
        label1 = tk.Label(frame_1, text='请输入视频链接：')
        entry_url = tk.Entry(frame_1, textvariable=self.url, highlightcolor='Fuchsia', highlightthickness=1, width=35)

        # set frame_2
        s_lable = tk.Label(frame_2, text='起始值：')
        e_lable = tk.Label(frame_2, text='结束值：')
        start = tk.Entry(frame_2, textvariable=self.start, highlightcolor='Fuchsia', highlightthickness=1, width=10)
        end = tk.Entry(frame_2, textvariable=self.end, highlightcolor='Fuchsia', highlightthickness=1, width=10)

        # set frame_3
        label2 = tk.Label(frame_3, text='请输入视频输出地址：')
        entry_path = tk.Entry(frame_3, textvariable=self.path, highlightcolor='Fuchsia', highlightthickness=1, width=35)
        down = tk.Button(frame_3, text='下载', font=('楷体', 12), fg='green', width=3, height=-1,
                         command=self.video_download)
        # set frame_4
        label_desc = tk.Label(frame_4, fg='black', font=('楷体', 12),
                              text='\n注意：支持youtube、twitter、腾讯、爱奇艺、优酷、bilibili等大部分主流网站视频下载、图片下载！')
        label_warning = tk.Label(frame_4, fg='blue', font=('楷体', 12), text='\nauthor:xiaofeng')

        # layout
        frame_1.pack()
        frame_2.pack()
        frame_3.pack()
        frame_4.pack()

        label1.grid(row=0, column=0)
        entry_url.grid(row=0, column=1)

        s_lable.grid(row=1, column=0)
        start.grid(row=1, column=1)
        e_lable.grid(row=1, column=2)
        end.grid(row=1, column=3)

        label2.grid(row=2, column=0)
        entry_path.grid(row=2, column=1)
        down.grid(row=2, column=2, ipadx=20)

        label_desc.grid(row=3, column=0)
        label_warning.grid(row=4, column=0)

    """
    视频下载
    """

    def video_download(self):
        # 正则表达是判定是否为合法链接
        url = self.url.get()
        path = self.path.get()
        if re.match(r'^https:/{2}\w.+$', url):
            if path != '':
                msgbox.showwarning(title='警告', message='下载过程中窗口如果出现短暂卡顿说明文件正在下载中！')
                try:
                    sys.argv = ['you-get', '-o', path, url]
                    you_get.main()
                except Exception as e:
                    print(e)
                    msgbox.showerror(title='error', message=e)
                msgbox.showinfo(title='info', message='下载完成！')
            else:
                msgbox.showerror(title='error', message='输出地址错误！')
        else:
            msgbox.showerror(title='error', message='视频地址错误！')

    def center(self):
        ws = self.root.winfo_screenwidth()
        hs = self.root.winfo_screenheight()
        x = int((ws / 2) - (self.w / 2))
        y = int((hs / 2) - (self.h / 2))
        self.root.geometry('{}x{}+{}+{}'.format(self.w, self.h, x, y))

    def event(self):
        self.root.resizable(False, False)
        self.center()
        self.root.mainloop()


if __name__ == '__main__':
    app = DownloadApp()
    app.event()

注：由于视频窗口是单线程，所以下载过程会一直卡顿（是正常的，因为处于下载中，下载完后会恢复），后续将会优化