python-librtmp problem

download.py

import sys
import librtmp
import requests
from lxml import etree

PAGE_URL = 'http://www.crunchyroll.com/parasyte-the-maxim-/episode-1-metamorphosis-662583'
XML_URL = 'http://www.crunchyroll.com/xml/?req=RpcApiVideoPlayer_GetStandardConfig&media_id=662583'

response = requests.post(XML_URL, data={'current_page': PAGE_URL})
document = etree.XML(response.text.encode('utf-8'))
file = document.xpath('//stream_info/file/text()')[0]
host = document.xpath('//stream_info/host/text()')[0]

def download_video():
    print 'rtmpdump -r "{host}" -y "{file}" -o video2.flv'.format(file=file, host=host)
    connection = librtmp.RTMP(host, playpath=file, timeout=60)
    connection.connect()
    stream = connection.create_stream()
    while True:
        data = stream.read(1024)
        if not data:
            break
        yield data

def sizeof_fmt(num, suffix='B'):
    for unit in ['','Ki','Mi','Gi','Ti','Pi','Ei','Zi']:
        if abs(num) < 1024.0:
            return "%3.1f%s%s" % (num, unit, suffix)
        num /= 1024.0
    return "%.1f%s%s" % (num, 'Yi', suffix)

with open('video.flv', 'wb') as fle:
    size = 0
    for block in download_video():
        size += len(block)
        fle.write(block)
        sys.stdout.write('{}      \r'.format(sizeof_fmt(size)))

print ''
print 'Complete!'