 According to the standard, S5 encoder shall at least consist of a base S5 encoder; and a S5 decoder shall at least consist of a base S5 decoder.The base S5 encoder compresses multichannel audio information by downmixing the f-channel signal to g channels and produces sparse spatial data according to an inverse coding model, which approaches the localization and ambiance of the original signal.The inverse coding model directly constructs an upmix of h channels from the audio downmix and its associated spatial data.