A method for encoding a sound signal using a CELP core module and supplementary codec modules of a sound signal encoder comprising: allocating to the supplementary codec modules a bit-budget ( b supplementary) fluctuating based on the sound signal; subtracting, from a total codec bit-budget ( b total), the supplementary codec modules bit-budget ( b supplementary) to determine a fluctuating CELP core module bit-budget ( b core); allocating the CELP core module bit-budget ( b core) to (a) a plurality of first parts, including at least one of LP filter coefficients, a CELP adaptive codebook, a CELP adaptive codebook gain and a CELP innovation codebook gain, and (b) a second part, including a CELP innovation codebook, of the CELP core module, comprising: storing bit-budget allocation tables assigning, for each of a plurality of fixed candidate intermediate bit rates, respective bit-budgets for encoding the first CELP core module parts; determining on the basis of the CELP core module bit-budget ( b core) a fluctuating CELP core module bit rate; selecting one of the intermediate bit rates based on the determined CELP core module bit rate; allocating to the first CELP core module parts and from the CELP core module bit-budget ( b core) the respective bit-budgets assigned by the bit-budget allocation tables for the selected intermediate bit rate; and allocating to the second CELP core module part a bit-budget remaining from the CELP core module bit-budget ( b core) after allocating to the first CELP core module parts the respective bit-budgets assigned by the bit-budget allocation tables for the selected intermediate bit rate; and encoding the audio signal using the supplementary codec modules and the first and second CELP core module parts using the respective allocated bit-budgets. allocating to the supplementary codec modules a bit-budget ( b supplementary) fluctuating based on the sound signal; subtracting, from a total codec bit-budget ( b total), the supplementary codec modules bit-budget ( b supplementary) to determine a fluctuating CELP core module bit-budget ( b core); allocating the CELP core module bit-budget ( b core) to (a) a plurality of first parts, including at least one of LP filter coefficients, a CELP adaptive codebook, a CELP adaptive codebook gain and a CELP innovation codebook gain, and (b) a second part, including a CELP innovation codebook, of the CELP core module, comprising: storing bit-budget allocation tables assigning, for each of a plurality of fixed candidate intermediate bit rates, respective bit-budgets for encoding the first CELP core module parts; determining on the basis of the CELP core module bit-budget ( b core) a fluctuating CELP core module bit rate; selecting one of the intermediate bit rates based on the determined CELP core module bit rate; allocating to the first CELP core module parts and from the CELP core module bit-budget ( b core) the respective bit-budgets assigned by the bit-budget allocation tables for the selected intermediate bit rate; and allocating to the second CELP core module part a bit-budget remaining from the CELP core module bit-budget ( b core) after allocating to the first CELP core module parts the respective bit-budgets assigned by the bit-budget allocation tables for the selected intermediate bit rate; and storing bit-budget allocation tables assigning, for each of a plurality of fixed candidate intermediate bit rates, respective bit-budgets for encoding the first CELP core module parts; determining on the basis of the CELP core module bit-budget ( b core) a fluctuating CELP core module bit rate; selecting one of the intermediate bit rates based on the determined CELP core module bit rate; allocating to the first CELP core module parts and from the CELP core module bit-budget ( b core) the respective bit-budgets assigned by the bit-budget allocation tables for the selected intermediate bit rate; and allocating to the second CELP core module part a bit-budget remaining from the CELP core module bit-budget ( b core) after allocating to the first CELP core module parts the respective bit-budgets assigned by the bit-budget allocation tables for the selected intermediate bit rate; and encoding the audio signal using the supplementary codec modules and the first and second CELP core module parts using the respective allocated bit-budgets.