All of the codec decoding is done "on the fly", and the processing power needed is not great. Every time you select DD, DTS, TrueHD, DTS-MA, there is on the fly decoding happening somewhere, whether your player, or your receiver.
You might want to be more specific with details, ask Tom directly, or link the podcast with specific mention of the time mark when this is discussed. (I probably won't listen to it, but someone else might.)