Currently Theora decoding is not provided by any hardware. The Elphel 333 can encode a theora stream though.
But, there is an accepted proposal to Google Summer Of Code 2006 that the goal is to do a Hardware Implementation of the Theora Decoding Algorithm.
The intent is to get a FPGA embeded system decoding Theora Streams in real-time.
The complete text of the project proposed is here:
As soon as possible, there will be more specific information about the implementation, but to begin, there are two presentations that the author of the SOC proposal presented in his University: