Apparatus and method for spatial audio object coding employing hidden objects for signal mixture manipulation

An apparatus for encoding one or more audio objects to obtain an encoded signal, wherein the apparatus comprises:

• a downmixer for downmixing the one or more audio objects to acquire one or more unprocessed downmix signals,
• a processing module for processing the one or more unprocessed downmix signals to acquire one or more processed downmix signals, wherein the processing module is configured to process the one or more unprocessed downmix signals by encoding the one or more unprocessed downmix signals to acquire the one or more processed downmix signals,
• a signal calculator for calculating one or more additional signals, wherein the signal calculator comprises a decoding unit and a combiner, wherein the decoding unit is configured to decode the one or more processed downmix signals to acquire one or more decoded signals, and wherein the combiner is configured to generate each of the one or more additional signals by generating a difference signal between one of the one or more decoded signals and one of the one or more unprocessed downmix signals,
• an object information generator for generating parametric audio object information for the one or more audio objects and additional parametric information for the one or more additional signals, and
• an output interface for outputting the encoded signal, the encoded signal comprising the parametric audio object information for the one or more audio objects and the additional parametric information for the one or more additional signals,
• wherein an audio object energy value is assigned to each one of the one or more audio objects,
• wherein an additional energy value is assigned to each one of the one or more additional signals,
• wherein the object information generator is configured to determine a reference energy value, so that the reference energy value is greater than or equal to the audio object energy value of each of the one or more audio objects, and so that the reference energy value is greater than or equal to the additional energy value of each of the one or more additional signals,
• wherein the object information generator is configured to determine the parametric audio object information by determining an audio object level difference for each audio object of the one or more audio objects, so that said audio object level difference indicates a ratio of the audio object energy value of said audio object to the reference energy value, or so that said audio object level difference indicates a difference between the reference energy value and the audio object energy value of said audio object, and
• wherein the object information generator is configured to determine the additional object information by determining an additional object level difference for each additional signal of the one or more additional signals, so that said additional object level difference indicates a ratio of the additional energy value of said additional signal to the reference energy value, or so that said additional object level difference indicates a difference between the reference energy value and the additional energy value of said additional signal.

A method for encoding one or more audio objects to obtain an encoded signal, wherein the method comprises:

• downmixing the one or more audio objects to obtain one or more unprocessed downmix signals,
• processing the one or more unprocessed downmix signals to obtain one or more processed downmix signals, wherein processing the one or more unprocessed downmix signals is conducted by encoding the one or more unprocessed downmix signals to obtain the one or more processed downmix signals,
• calculating one or more additional signals by decoding the one or more processed downmix signals to obtain one or more decoded signals, and by generating each of the one or more additional signals by generating a difference signal between one of the one or more decoded signals and one of the one or more unprocessed downmix signals,
• generating parametric audio object information for the one or more audio objects and additional parametric information for the one or more additional signals, and
• outputting the encoded signal, the encoded signal comprising the parametric audio object information for the one or more audio objects and the additional parametric information for the one or more additional signals.