of the frame uses a variably distributed bit allocation on a sub-band-by-sub-band basis. The apparatus caused to decode the encoded values of the frame based on a defined allocation of bits wherein decoding the at least one azimuth index and/or at least one elevation index of the frame uses a variably distributed bit allocation on a sub-band-by-sub-band basis may further be caused to: determine an initial allocation of bits distribution used to decode the at least one azimuth index and/or at least one elevation index for each sub-band based on the at least one energy ratio value for each sub-band; determine a reduced allocation of bits distribution based on the initial allocation of bits distribution and an allocation of bits distribution for decoding at least one energy ratio value of the frame; and decode the at least one azimuth index and/or at least one elevation index of the frame based on the reduced allocation of bits distribution. The apparatus caused to decode the at least one azimuth index and/or at least one elevation index of the frame based on the reduced allocation of bits distribution may further be caused to: determine an allocation of bits for decoding the at least one azimuth index and/or at least one elevation index for a sub-band based on the reduced distribution; entropy decode the at least one azimuth index and/or at least one elevation index based on a signalling bit indicating entropy encoding and fixed rate decoding otherwise; distribute any available bits from the difference of the allocation of bits for decoding the at least one azimuth index and/or at least one elevation index for a sub-band and the sum of the number of bits decoding the sub-band and the signalling bit for further allocation of bits for decoding the at least one azimuth index and/or at least one elevation index for a further sub- band or decrease a further allocation of bits for decoding the at least one azimuth index and/or at least one elevation index for a further sub-band by one bit otherwise. The apparatus caused to decode the at least one azimuth index and/or at least one elevation index of the frame based on the reduced allocation of bits distribution may further be caused to: determine an allocation of bits for decoding the at least one azimuth index and/or at least one elevation index for a last sub-band based on the reduced distribution; and fixed rate decode the at least one azimuth