An example apparatus includes a memory configured to store the audio data; and one or more processors in communication with the memory, the one or more processors configured to: decode, from an encoded audio bitstream, a unique identifier for each of a plurality of subbands of audio data; perform inverse pyramid vector quantization (PVQ) using a compact map to reconstruct a residual vector for each subband of the plurality of subbands of the audio data based on the unique identifier for the respective subband of the plurality of subbands of the audio data, wherein the compact map is generated using structural unification of vectors across subbands and relational compression, and wherein the unique identifiers correspond to codevectors; and reconstruct, based on the residual vectors and energy scalars for each subband, the plurality of subbands of the audio data.