9. The apparatus as claimed in any of claims 5 to 8, wherein the means for encoding on a sub-band-by-sub-band basis by determining a reduced distribution of the third number of bits on a sub-band-by-sub-band basis, the reduced estimate based on the initial estimate and the defined allocation of the second number of bits is 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. 10. The apparatus as claimed in any of claims 1 to 9, wherein 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 is 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. 11. The apparatus as claimed in any of claims 1 to 10, wherein the means for is further for: storing and/or transmitting the encoded at least one energy ratio value of the frame and at least one azimuth value and/or at least one elevation value. 12. 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 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. 13. The apparatus as claimed in claim 12, wherein the means for decoding the encoded values of the frame based on a defined allocation of bits wherein decoding