second number of bits may be further for uniformly reducing on a sub-band-by-sub- band basis an allocation of bits for encoding the at least one azimuth index and/or at least one elevation index. The means for encoding the at least one azimuth value and/or at least one elevation value of the frame based on a defined allocation of a third number of bits from the first number of bits, wherein the third number of bits is variably distributed on a sub-band-by-sub-band basis may be further for at least one of: assigning indexes for encoding in increasing order of the distance from the frontal direction; assigning the index in increasing order of the azimuth value. The means for may be further for: storing and/or transmitting the encoded at least one energy ratio value and at least one azimuth value and/or at least one elevation value. According to a second aspect there is provided an apparatus comprising means for: receiving encoded values for sub-bands of a frame of an audio signal, the values comprising at least one azimuth index, at least one elevation index and at least one energy ratio value for each sub-band; decoding 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. The means for decoding 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 be further for: determining 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; determining 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 decoding the at least one azimuth index and/or at least one elevation index of the frame based on the reduced allocation of bits distribution.