My suggestion is to download them from a site like Limewire or Frostwire then you can watch them any time you want
Where Can I Watch Free Movies With My Slow Broadband Connection?
You can try moviewatchlist.com for that purpose. The videos hosted on American servers like of youtube.com buffers faster than the Chinese one. You should start the video and stop it to play and let the video buffering to complete and play after the video completes it buffering to watch movies uninterrupted.