of bits, wherein the third number of bits is variably distributed on a sub-band-by-sub- band basis is further for: 

determining an initial estimate for the distribution of the third number of bits on a sub-band-by-sub-band basis, the initial estimate based on the at least one energy ratio value associated with the sub-band; 

spatial quantizing the at least one azimuth value and/or at least one elevation value based on the initial estimate for the distribution of the third number of bits on a sub-band-by-sub-band basis to generate at least one azimuth index and/or at least one elevation index for each sub-band. 

5. The apparatus as claimed in claim 4, 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 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. 

6. The apparatus as claimed in claim 5, 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 encoding on a sub-band-by-sub-band basis by: 

determining an allocation of bits for encoding the at least one azimuth index and/or at least one elevation index for a sub-band based on the reduced distribution; 

estimating a number of bits required to entropy encode the at least one azimuth index and/or at least one elevation index; 

entropy encoding the at least one azimuth index and/or at least one elevation index based on the number of bits required to entropy encode the at least one azimuth index and/or at least one elevation index being less than the allocation of 

