Patent ID: 7783051

Claim:
A method for decoding an audio signal performed by an audio coding system, comprising: receiving a downmix signal comprising at least one object signal; receiving object information determined when the downmix signal is generated; receiving mix information for controlling the at least one object signal; bypassing processing the downmix signal using downmix processing information if the downmix signal corresponds to a mono signal; and generating multi-channel information including at least one gain modification factor using the object information and the mix information if the downmix signal corresponds to the mono signal, wherein: the gain modification factor corresponds to a time-subband-variant factor for controlling gain of the downmix signal; the gain modification factor is used to modify a gain of the downmix signal; the downmix processing information is estimated based on the object information and the mix information; the object information includes at least one of object level information and object correlation information; the multi-channel information includes at least one of a channel level difference, an inter channel correlation, and a channel prediction coefficient; the downmix signal corresponds to the mono signal or a stereo signal; the multi-channel information is used to generate a multi-channel signal using the downmix signal; and a number of channels of the multi-channel signal is more than a number of channels of the downmix signal.