1984 is a Pearson based temporal denoiser that uses a few statistical analysis techniques to reduce noise in rendered output from pathtracers.
Basically it looks for deviants in the population and forces them to conform to the beautiful order of the all seeing eye..
It is currently implemented as a c++ library with a Nuke plugin interface and was originally designed to work with the Arnold Renderer but is built to be renderer agnostic as long as a tracer has the ability to write out certain variables it will work with it just fine.