下载youtube视频的python脚本

Question

在给出youtube视频url时，我首先下载视频页面并提取javascript对象

<script>var ytplayer = ytplayer .....  </script>

我得到了

^{pr2}$

我发现keyadaptive_fmts和url编码的_fmt_stream_map包含多个百分比编码形式的url。 我从url编码的流图中取一个url，它看起来像这样

https://r1---sn-o3o-qxal.googlevideo.com/videoplayback?
ratebypass=yes&
signature=982E413BBE08CA5801420F9696E0F2ED691B99FA.D666D39D1A0AF066F76F12632A10D3B8076076CE&
lmt=1443906393476832&
expire=1446604919&
fexp=9406983%2C9408710%2C9414764%2C9416126%2C9417707%2C9421410%2C9422596%2C9423663&
itag=22&
dur=128.801&
source=youtube&
upn=pk2CEhVBeFM&
sver=3&
key=yt6&
id=o-AK-OlE5NUsbkp51EZY2yKuz5vsSGofgUvrvTtOrhC72e&
sparams=dur%2Cid%2Cinitcwndbps%2Cip%2Cipbits%2Citag%2Clmt%2Cmime%2Cmm%2Cmn%2Cms%2Cmv%2Cpl%2Cratebypass%2Crequiressl%2Csource%2Cupn%2Cexpire&
mime=video%2Fmp4&
ipbits=0&
pl=21&
ip=x.y.z.a&
initcwndbps=5405000&
requiressl=yes&
mn=sn-o3o-qxal&
mm=31&
ms=au&
mv=m&
mt=1446583222&
itag=22&
type=video/mp4

但当我把这个（上面的）url粘贴到浏览器中时，什么也没发生，我的意思是不能工作。 请帮帮我。在

还有

自适应和url编码的包含url的流映射有什么区别？在

Answer 1

在python2.7中，这是有效的：

import urlparse, urllib2

vid        = "vzS1Vkpsi5k"
save_title = "YouTube SpaceX - Booster Number 4 - Thaicom 8 06-06-2016"
url_init   = "https://www.youtube.com/get_video_info?video_id=" + vid

resp = urllib2.urlopen(url_init, timeout=10)
data = resp.read()
info =  urlparse.parse_qs(data)
title = info['title']

print "length:  ", info['length_seconds'][0] + " seconds"

stream_map   = info['adaptive_fmts'][0]
vid_info     = stream_map.split(",")

mp4_filename = save_title + ".mp4"

for video in vid_info:
    item = urlparse.parse_qs(video)

    #print 'quality: ', item['quality'][0]
    #print 'type:    ', item['type'][0]

    url_download  = item['url'][0]
    resp          = urllib2.urlopen(url_download)

    print resp.headers

    length  = int(resp.headers['Content-Length'])
    my_file = open(mp4_filename, "w+")

    done, i = 0, 0
    buff    = resp.read(1024)        
    while buff:

        my_file.write(buff)
        done += 1024
        percent = done * 100.0 / length
        buff = resp.read(1024)

        if not i%1000:                
            percent = done * 100.0 / length
            print str(percent) + "%"

        i += 1
    break