Spatial audio processing

An apparatus comprises at least one processor;

• and at least one memory including computer program code, which when executed by the at least one processor, causes the apparatus to:
• obtain spatial audio parameters that are descriptive of spatial characteristics of a sound field;
• estimate a signal energy of the sound field represented by a multi-channel input audio signal, wherein the apparatus is caused to estimate the signal energy of the sound field represented by the multi-channel input audio signal by computing a respective input signal energy for channels of the multi-channel input audio signal;
• and computing the signal energy as a sum of the input signal energies across channels of said multi-channel input audio signal;
• estimate, based on said signal energy and the obtained spatial audio parameters, respective output signal energies for channels of a multi-channel output audio signal according to a predefined loudspeaker layout;
• determine a maximum output energy across channels of said multi-channel output audio signal based on the estimated respective output signal energies;
• and
• derive, on basis of said maximum output energy, a gain value for adjusting sound reproduction gain in at least one of said channels of the multi-channel output audio signal in synthesis of the multi-channel output audio signal.

A method for processing a multi-channel input audio signal representing a sound field into a multi-channel output audio signal in accordance with a predefined loudspeaker layout, the method comprising for at least one frequency band:

• obtaining spatial audio parameters that are descriptive of spatial characteristics of said sound field;
• estimating a signal energy of the sound field represented by the multi-channel input audio signal by computing a respective input signal energy for channels of the multi-channel input audio signal;
• and computing the signal energy as a sum of the input signal energies across channels of said multi-channel input audio signal;
• estimating, based on said signal energy and the obtained spatial audio parameters, respective output signal energies for channels of the multi-channel output audio signal according to said predefined loudspeaker layout;
• determining a maximum output energy across channels of said multi-channel output audio signal based on the estimated respective output signal energies;
• and
• deriving, on basis of said maximum output energy, a gain value for adjusting sound reproduction gain in at least one of said channels of the multi-channel output audio signal.