Spatial audio rendering and encoding

1. A spatial audio rendering apparatus, comprising:

a first circuit for providing a residual downmix and data characterizing at least one audio object, the residual downmix corresponding to a downmix of audio components of an audio scene with the at least one audio object being removed;

a receiver for receiving a diffuseness parameter indicative of a degree of diffuseness of the residual downmix;

a first sound processor for generating a first set of signals for a spatial speaker configuration by applying a first transformation to the residual downmix, the first transformation being dependent on the diffuseness parameter;

a second sound processor for generating a second set of signals for the spatial speaker configuration by applying a second transformation to the residual downmix, the second transformation being dependent on the diffuseness parameter and comprising a decorrelation of at least one channel of the residual downmix;

a second circuit for generating a third set of signals for the spatial speaker configuration from the data characterizing the at least one audio object; and

an output circuit for generating an output set of signals for the spatial speaker configuration by combining the first, second and third set of signals;

wherein the diffuseness parameter is direction dependent.

2. The spatial audio rendering apparatus of claim 1 , wherein the diffuseness parameter comprises individual diffuseness values for different channels of the residual downmix.

3. The spatial audio rendering apparatus of claim 1 , wherein for at least one channel of the residual downmix, a contribution of the second transformation relative to a contribution of the first transformation in the output signal increases for the diffuseness parameter indicating an increased diffuseness.

4. The spatial audio rendering apparatus of claim 1 , wherein a combined energy of the first set of signals and the second set of signals is substantially independent of the diffuseness parameter.

5. The spatial audio rendering apparatus of claim 1 , wherein the second audio processor is configured to adjust an audio level of a first signal of the second set of signals in response to a distance of a speaker position associated with the first signal to at least one neighboring speaker position associated with a different signal of the second set of signals.

6. The spatial audio rendering apparatus of claim 1 , wherein the residual downmix comprises fewer channels than a number of speaker positions of the spatial speaker configuration, and wherein the second audio processor is configured to generate a plurality of signals of the second set of signals by applying a plurality of decorrelations to at least a first channel of the residual downmix.

7. The spatial audio rendering apparatus of claim 6 , wherein the second audio processor is configured to generate a further plurality of signals of the second set of signals by applying a plurality of decorrelations to a second channel of the residual downmix, the second channel not being a channel of the at least first channels.

8. The spatial audio rendering apparatus of claim 1 , wherein the second set of signals comprises fewer signals than a number of speaker positions in the spatial speaker configuration.

9. The spatial audio rendering apparatus of claim 1 , wherein the residual downmix comprises more channels than a number of speaker positions of the spatial speaker configuration, and wherein the second audio processor is configured to combine at least two channels of the residual downmix when generating the second set of signals.

10. The spatial audio rendering apparatus of claim 1 , wherein the second audio processor is configured to generate the second set of signals to correspond to a sideways rendering of audio from the second set of signals.

11. The spatial audio rendering apparatus of claim 1 , wherein the receiver is configured to receive a received downmix comprising the audio objects; and wherein the circuit for providing the residual downmix is configured to generate at least one audio object in response to the data characterizing the data objects, and to generate the residual downmix by extracting the at least one audio object from the received downmix.

12. The spatial audio rendering apparatus of claim 1 , wherein the spatial speaker configuration is different from a spatial sound representation of the residual downmix.

13. A method of generating spatial audio output signals, the method comprising:

providing a residual downmix and data characterizing at least one audio object, the residual downmix corresponding to a downmix of audio components of an audio scene with the at least one audio object being removed;

receiving a diffuseness parameter indicative of a degree of diffuseness of the residual downmix;

generating a first set of signals for a spatial speaker configuration by applying a first transformation to the residual downmix, the first transformation being dependent on the diffuseness parameter;

generating a second set of signals for the spatial speaker configuration by applying a second transformation to the residual downmix, the second transformation being dependent on the diffuseness parameter and comprising a decorrelation of at least one channel of the residual downmix;

generating a third set of signals for the spatial speaker configuration from the data characterizing the at least one audio object; and

generating an output set of signals for the spatial speaker configuration by combining the first, second and third set of signals;

wherein the diffuseness parameter is direction dependent.