Patent ID: 7406412

Claim:
A method for encoding an audio signal that comprises: receiving spectral components that represent spectral content of the audio signal; applying a perceptual model to the spectral components to obtain a first masking curve that represents perceptual masking effects of the audio signal; deriving an estimated value of a coding parameter that specifies an offset between a second masking curve and the first masking curve, wherein the estimated value of the coding parameter is derived in response to a number of bits that are available for encoding the audio signal, and wherein the deriving of the estimated value of the coding parameter comprises: selecting an initial value for the coding parameter; determining a first number of bits in response to the initial value of the coding parameter to use in quantizing the spectral components; determining a second number of bits from a difference between the first number of bits and a third number of bits, wherein the third number of bits corresponds to the number of bits that are available for encoding the audio signal; and deriving the estimated value of the coding parameter in response to the initial value of the coding parameter and the second number of bits; obtaining an optimum value of the coding parameter by modifying the estimated value of the coding parameter in an iterative process that searches for the optimum value of the coding parameter according to the perceptual model; generating encoded spectral components by quantizing spectral components according to the second masking curve, wherein resolution of the quantizing is responsive to the first masking curve and the coding parameter such that the optimum value of the coding parameter minimizes perceptibilty of quantizing noise according to the perceptual model; and assembling a representation of the encoded spectral components into an output signal.