Patent ID: 7613607

Claim:
A method, comprising: determining, at an apparatus, an old fixed codebook gain correction factor {circumflex over (γ)} gc old from an index corresponding to a fixed codebook gain, wherein a coded audio signal comprises indices that represent audio signal parameters comprising at least the fixed codebook gain representing a first characteristic of the audio signal and an adaptive codebook gain; adjusting the old fixed codebook gain correction factor {circumflex over (γ)} gc old in order to achieve an enhanced first characteristic, thereby obtaining desired gain β·{circumflex over (γ)} gc old ; determining an old adaptive codebook gain value g p — old from the index further corresponding to the adaptive codebook gain; and determining a new index value from a table relating index values to fixed codebook gain correction factors and relating the index values to adaptive codebook gain values by minimizing an error |β·{circumflex over (γ)} gc old −{circumflex over (γ)} gc new | between the desired gain and a new fixed codebook gain correction factor {circumflex over (γ)} gc new corresponding to the new index value such that no audible error is introduced to a new adaptive codebook gain value g p — new new corresponding to the new index value.