Patent ID: 8705779

Claim:
A surround sound virtualization apparatus, comprising: an audio decoder, wherein the audio decoder comprises: a surround virtualization unit to perform head-related transfer function (HRTF) filtering to a plurality of channel signals, and a domain transform unit to transform a plurality of output signals of the surround virtualization unit into a time domain; and a time delay unit to provide time delays on a per signal basis to a plurality of output signals transformed by the domain transform unit, wherein the domain transform unit comprises: a signal addition unit to add a proper subset of output signals of the surround virtualization unit into at least one added output signal; and an inverse transform unit to transform the at least one added output signal into the time domain, wherein a plurality of signals input to the inverse transform unit is less than the plurality of channel signals output from the surround virtualization unit, the HRTF filtering is performed inside the audio decoder and the time delay unit provides the time delay outside of the audio decoder, and the time delays are related to an interaural time difference.