Patent ID: 7318027

Claim:
A method of processing an audio signal comprising: receiving a signal conveying initial scaled values and initial scale factors representing spectral components of the audio signal, wherein each initial scale factor is associated with one or more initial scaled values, each initial scaled value is scaled according to its associated initial scale factor, and each initial scaled value and associated initial scale factor represent the value of a respective spectral component; generating coded spectral information by pertforming a coding process that is responsive to initial spectral information that comprises at least some of the initial scale factors; deriving one or more first control parameters in response to the initial scale factors and a first bit-rate requirement; allocating bits according to a first bit allocation process in response to the one or more first control parameters; obtaining quantized scaled values by quantizing at least some of the initial scaled values using quantizing resolutions based on numbers of bits allocated by the first bit allocation process; deriving one or more second control parameters in response to at least some of the initial scale factors, one or more modified scale factors and a second bit-rate requirement, wherein the one or more modified scale factors are obtained by: analyzing the initial spectral information with respect to a synthesis process to be applied to the coded spectral information in a decoding method that generates synthesized spectral components represented by synthesized scaled values and associated synthesized scale factors to identify one or more potentially unnormalized synthesized scaled values, wherein the synthesis process is quasi-inverse to the coding process, and generating the one or more modified scale factors to represent modified values of initial scale factors in the initial spectral information corresponding to synthesized scale factors that are associated with at least some of the one or more potentially unnormalized synthesized scaled values to compensate for loss of normalization of the identified potentially unnormalized synthesized scaled values; and assembling encoded information into an encoded signal, wherein the encoded information represents the quantized scaled values, at least some of the initial scale factors, the coded spectral information, the one or more first control parameters and the one or more second control parameters.