Method and apparatus for compressing and decompressing a higher order Ambisonics signal representation
A method and apparatus for decompressing a Higher Order Ambisonics (HOA) signal representation is disclosed. The apparatus includes an input interface that receives an encoded directional signal and an encoded ambient signal and an audio decoder that perceptually decodes the encoded directional signal and encoded ambient signal to produce a decoded directional signal and a decoded ambient signal, respectively. The apparatus further includes an extractor for obtaining side information related to the directional signal and an inverse transformer for converting the decoded ambient signal from a spatial domain to an HOA domain representation of the ambient signal. The apparatus also includes a synthesizer for recomposing a Higher Order Ambisonics (HOA) signal from the HOA domain representation of the ambient signal and the decoded directional signal. The side information includes a direction of the directional signal selected from a set of uniformly spaced directions.
1. A method for decompressing a compressed Higher Order Ambisonics (HOA) signal, the method comprising:
receiving the compressed HOA signal;
receiving directional information associated with the compressed HOA signal, wherein the directional information includes information regarding a set of active directions;
decoding the compressed HOA signal to determine a decoded directional HOA signal and a decoded ambient HOA signal, wherein the decoded directional HOA signal is decoded based on the set of active directions;
performing order extension on the decoded ambient HOA signal to obtain an order extended representation of the decoded ambient HOA signal, wherein the order extension is performed by appending signals with zero-valued samples to the decoded ambient HOA signal; and
recomposing a decoded HOA representation from the order extended representation of the decoded ambient HOA signal and the decoded directional HOA signal.
2. The method of claim 1 , wherein the decoded HOA representation has a first order greater than one.
3. The method of claim 2 , wherein the decoded ambient HOA signal has a second order that is less than the first order of the decoded HOA representation.
4. A non-transitory computer-readable medium having stored thereon instructions, that when executed by one or more processors, cause one or more processors to perform the method of claim 1 .
5. An apparatus for decompressing a compressed Higher Order Ambisonics (HOA) signal, the apparatus comprising:
an input interface that receives the compressed HOA signal and that receives directional information associated with the compressed HOA signal, wherein the directional information includes information regarding a set of active directions;
an audio decoder that decodes the compressed HOA signal to determine a decoded directional HOA signal and a decoded ambient HOA signal, wherein the decoded directional HOA signal is decoded based on the set of active directions;
a processor for performing order extension on the decoded ambient HOA signal to obtain an order extended representation of the decoded ambient HOA signal, wherein the order extension is performed by appending signals with zero-valued samples to the decoded ambient HOA signal; and
a synthesizer for recomposing a decoded HOA representation from the order extended representation of the decoded ambient HOA signal and the decoded directional HOA signal.
6. The apparatus of claim 5 , wherein the decoded HOA representation has a first order greater than one.
7. The apparatus of claim 6 , wherein the decoded ambient HOA signal has a second order that is less than the first order of the decoded HOA representation.