I learnt about Disney releasing its PTex source code and following that, support for a library to read, write, cache and filter ptex files. Here's the news I was reading:
Disney releases open-source 3dcode
I looked up some resources pertaining to PTex. It stands for Per-face Texture. However, I did not really have time to read and deeply understand what ptex is, and how actually works, but these are some links for you to read up.
Ptex demonstration with explanation on www.youtube.com:
Disney Animation Studios Website: http://disneyanimation.com/
Ptex official website: http://ptex.us/