you are too lazy.
do something for yourself like reading streamlink's documentation.
Code:
C:\STREAMLINK>streamlink --stream-url http://www.ustream.tv/channel/20881817 best
Code:
http://c742eece-lp-live.ums.ustream.tv/playlist/auditorium/channel/20881817/3/playlist.m3u8?token=20897476_1500204785918&appType=11&appVersion=2&chunkingType=improved&sgn=99ba2c893bcacee561a0efe37e1370f68f027128&cdnHost=uhs-akamai.ustream.tv/