Pine 64 as a NAS media centre

[joe]

I don't know what kind of bandwidth you need, but IIRC, the Pine64 only has USB 2 connections and no SATA controller.  I don't know whether USB 2 is fast enough to stream say a 4K video.

Yes , 
is not sata controller , but you can buy usb hub adapter to External usb sata case input your sata hard drive , but this usb 2.0 reality speed bandwidth is enough for 4k video stream or not , i don't know , because Linux OS or new version android 5.1.1 have not Download , can't test ............ 

but saw they player 4k video use class 10 sd card is enough  , you think how speed can read 4k this card bandwidth? 
and this time no one report sd card or use usb hub adapter to External usb sata case read and write speed bandwidth , so this is no idea now