Method and apparatus for encoding and decoding an hoa representation

An apparatus for encoding an ambisonics signal representation of a sound field to determine a mezzanine ambisonics signal representation, the apparatus comprising:

• a first receiver configured to receive a first multi-channel signal comprising a first channels O corresponding to O Higher Order Ambisonics (HOA) coefficient sequences;
• a second receiver configured to receive transforming information for transforming the first multi-channel signal of the first number of channels O to the mezzanine ambisonics signal representation, wherein the transforming information includes a matrix comprising mapping information for mapping the O HOA coefficient sequences to O virtual loudspeaker signals, wherein the matrix size is based on an order N of the HOA coefficient sequences;
• and
• a processing unit configured to transform the first multi-channel signal to a second multi-channel signal based on a multiplication of the first multi-channel signal with the matrix information, wherein the mezzanine ambisonics signal representation is represented by the second multi-channel signal, and wherein the second multi-channel signal comprises a second number of channels I corresponding to groups of virtual loudspeaker signals.

A method for decoding a mezzanine ambisonics signal representation to determine a reconstructed ambisonics signal representation of a sound field having an order N, the method comprising:

• receiving, by a processor configured to decode the mezzanine ambisonics signal representation, a first multi-channel signal of the mezzanine ambisonics signal representation, the first multi-channel signal of the mezzanine ambisonics signal representation having a first number of channels I;
• receiving, by the processor, transforming information for decoding the first multi-channel signal of the mezzanine ambisonics signal representation, wherein the transforming information includes matrix information for mapping O number of virtual loudspeakers to O sequences of Higher Order Ambisonics (HOA) coefficient sequences that represent the reconstructed ambisonics signal representation, wherein O depends on the order N;
• and
• transforming, by the processor, the first multi-channel signal to a second multi-channel signal, wherein the second multi-channel signal represents the reconstructed ambisonics signal representation, wherein the transforming comprises de-grouping the I channels to O de-grouped channel and wherein the transforming is based at least in part on the transforming information.