An earlier post recommended ProRes for playback off a MacMini.
I am making a 12 minute piece to be projected at a live performance.
My source files are multiple and I am making a layered AE piece, very
painterly using D1 square pixel settings (for the 16 by 9 format but smaller files)
Someone recommended I consider H264 and was not keen on AIC.
If I understand correctly, you will be playing off a Mac Mini connected to some sort of display?
ProRes is an excellent choice for this type of scenario.
It's actually easier to decode than H.264, and is a much better fit than AIC (which should die).
So yes, ProRes all the way :)
Just in case I misunderstood your post, and you're looking for real-time playback on Windows - then you should indeed use H.264, and use a fast, multithreaded player like Media Player Classic - Home Cinema.
QuickTime on Windows is absolutely dreadful, especially the ProRes decoder :)