A method for decoding an encoded audio bitstream is disclosed. The method includes receiving the encoded audio bitstream and decoding the audio data to generate a decoded lowband audio signal. The method further includes extracting high frequency reconstruction metadata and filtering the decoded lowband audio signal with an analysis filterbank to generate a filtered lowband audio signal. The method also includes extracting a flag indicating whether either spectral translation or harmonic transposition is to be performed on the audio data and regenerating a highband portion of the audio signal using the filtered lowband audio signal and the high frequency reconstruction metadata in accordance with the flag. The high frequency regeneration is performed as a post-processing operation with a delay of 3010 samples per audio channel.

An apparatus comprising means configured to: generate spatial audio signal directional metadata parameters for a block of time-frequencies; generate encoded spatial audio signal directional metadata parameters (108) for a block of time-frequencies based on a first quantization resolution (203); compare a number of bits used for the encoded spatial audio signal directional parameters (108) for the block of time-frequencies based on the first quantization resolution against a determined number of bits; output or store the encoded spatial audio signal directional metadata parameters for a block of time-frequencies (108) based on a first quantization resolution when the number of bits used for the encoded spatial audio signal directional parameters for the block of time-frequencies (108) based on the first quantization resolution is less than a determined number of bits (217); generate encoded spatial audio signal directional metadata parameters (108) for the block of time-frequencies based on a second quantization resolution when the number of bits used for the encoded spatial audio signal directional parameters for the block of time-frequencies (108) based on the first quantization resolution is more than the determined number of bits and a difference between the determined number of bits and the number of bits used for the encoded spatial audio signal directional parameters (108) for the block of time-frequencies based on the first quantization resolution is less than a determined number of bits is within a determined threshold (217); generate encoded spatial audio signal directional metadata parameters (108) for the block of time-frequencies based on a third quantization resolution when the number of bits used for the encoded spatial audio signal directional parameters (108) for the block of time-frequencies based on the first quantization resolution is more than the determined number of bits and the difference between the determined number of bits and the number of bits used for the encoded spatial audio signal directional parameters (108) for the block of time-frequencies based on the first quantization resolution is greater than the determined threshold, wherein the third quantization resolution is determined such that a number of bits used for the encoded spatial audio signal directional parameters for the block of time-frequencies based on the third quantization resolution is always equal to or less than the determined number of bits (217).

A method for decoding an encoded audio bitstream is disclosed. The method includes receiving the encoded audio bitstream and decoding the audio data to generate a decoded lowband audio signal. The method further includes extracting high frequency reconstruction metadata and filtering the decoded lowband audio signal with an analysis filterbank to generate a filtered lowband audio signal. The method also includes extracting a flag indicating whether either spectral translation or harmonic transposition is to be performed on the audio data and regenerating a highband portion of the audio signal using the filtered lowband audio signal and the high frequency reconstruction metadata in accordance with the flag.

A method for decoding an encoded audio bitstream is disclosed. The method includes receiving the encoded audio bitstream and decoding the audio data to generate a decoded lowband audio signal. The method further includes extracting high frequency reconstruction metadata and filtering the decoded lowband audio signal with an analysis filterbank to generate a filtered lowband audio signal. The method also includes extracting a flag indicating whether either spectral translation or harmonic transposition is to be performed on the audio data and regenerating a highband portion of the audio signal using the filtered lowband audio signal and the high frequency reconstruction metadata in accordance with the flag.

Methods and apparatus for decoding a compressed Higher Order Ambisonics (HOA) representation of a sound or soundfield. The method may include receiving a bit stream containing the compressed HOA representation and decoding, based on a determination that there are multiple layers, the compressed HOA representation from the bitstream to obtain a sequence of decoded HOA representations. A first subset of the sequence of decoded HOA representations is determined based only on corresponding ambient HOA components. A second subset of the sequence of decoded HOA representations is determined based on corresponding ambient HOA components and corresponding predominant sound components. For a frame k, the sequence of decoded HOA representations are represented at least in part by

[00001]${\widehat{c}}_n\left(k-1\right)=\left\{\begin{array}{l}{\widehat{c}}_{\text{AMB},n}\left(k-1\right)\hfill \\ {\widehat{c}}_n\left(k-1\right)={\widehat{c}}_{\text{PS},n}\left(k-1\right)+{\widehat{c}}_{\text{AMB},n}\left(k-1\right),\hfill \end{array}\begin{array}{c}\text{for n in the first subset}\\ \text{for n in the second subset}\end{array}\right)$

where

[00002]${\widehat{c}}_{\text{AMB,}n}\left(k-1\right)$

corresponds to the corresponding ambient HOA components and

[00003]