Quantizing spatial components based on bit allocations determined for psychoacoustic audio coding

1. A device configured to encode scene-based audio data, the device comprising:

a memory configured to store scene-based audio data; and

one or more processors configured to:

perform spatial audio encoding that includes application of a linear invertible transform with respect to the scene-based audio data to obtain a foreground audio signal and a corresponding spatial component, the spatial component defining spatial characteristics of the foreground audio signal;

perform psychoacoustic audio encoding with respect to the foreground audio signal to obtain an encoded foreground audio signal;

determine, when performing psychoacoustic audio encoding with respect to the foreground audio signal, a first bit allocation for the foreground audio signal;

determine, based on the first bit allocation for the foreground audio signal, a second bit allocation for the spatial component, wherein, to determine the second bit allocation, the one or more processors are configured to:

perform a shape and gain analysis with respect to the foreground audio signal to obtain a shape and a gain representative of the foreground audio signal;

perform quantization with respect to the gain to obtain a course quantized gain and one or more fine quantized residuals; and

determine, based on a number of bits allocated to the course quantized gain and each of the one or more fine quantized residuals, the second bit allocation;

quantize, based on the second bit allocation for the spatial component, the spatial component to obtain a quantized spatial component; and

specify, in a bitstream, the encoded foreground audio signal and the quantized spatial component.

2. The device of claim 1 , wherein the one or more processors are configured to perform the psychoacoustic audio encoding according to a compression algorithm with respect to the foreground audio signal to obtain the encoded foreground audio signal.

3. The device of claim 1 , wherein the one or more processors are configured to:

determine a spectral perceptual importance of the foreground audio signal relative to a soundfield represented by the scene-based audio data; and

determine, based on the spectral perceptual importance, the first bit allocation.

4. The device of claim 3 , wherein the one or more processors are configured to:

determine, based on the spectral perceptual importance and the number of bits allocated to the course quantized gain, a static spatial bit distribution;

determine, based on the number of bits allocated to each of the one or more fine quantized residuals, a dynamic spatial bit distribution; and

determine, based on the static spatial bit distribution and the dynamic spatial bit distribution, the second bit allocation.

5. The device of claim 1 , wherein the scene-based audio data comprises ambisonic coefficients corresponding to an order greater than one.

6. The device of claim 1 , wherein the scene-based audio data comprises ambisonic coefficients corresponding to an order greater than zero.

7. The device of claim 1 , wherein the scene-based audio data comprises audio data defined in a spherical harmonic domain.

8. The device of claim 7 ,

wherein the foreground audio signal comprises a foreground audio signal defined in the spherical harmonic domain, and

wherein the spatial component comprises a spatial component defined in the spherical harmonic domain.

9. The device of claim 1 , wherein the scene-based audio data includes mixed-order ambisonic audio data.

10. The device of claim 1 , further comprising a microphone configured to capture the scene-based audio data.

11. A method of encoding scene-based audio data, the method comprising:

performing spatial audio encoding that includes application of a linear invertible transform with respect to the scene-based audio data to obtain a foreground audio signal and a corresponding spatial component, the spatial component defining spatial characteristics of the foreground audio signal;

performing psychoacoustic audio encoding with respect to the foreground audio signal to obtain an encoded foreground audio signal;

determining, when performing psychoacoustic audio encoding with respect to the foreground audio signal, a first bit allocation for the foreground audio signal;

determining, based on the first bit allocation for the foreground audio signal, a second bit allocation for the spatial component, wherein determining the second bit allocation comprises:

performing a shape and gain analysis with respect to the foreground audio signal to obtain a shape and a gain representative of the foreground audio signal;

performing quantization with respect to the gain to obtain a course quantized gain and one or more fine quantized residuals; and

determining, based on a number of bits allocated to the course quantized gain and each of the one or more fine quantized residuals, the second bit allocation;

quantizing, based on the second bit allocation for the spatial component, the spatial component to obtain a quantized spatial component; and

specifying, in a bitstream, the encoded foreground audio signal and the quantized spatial component.

12. A device configured to decode a bitstream representative of encoded scene-based audio data, the device comprising:

a memory configured to store the bitstream, the bitstream including an encoded foreground audio signal and a corresponding quantized spatial component that defines spatial characteristics of the foreground audio signal, the encoded foreground audio signal and the corresponding spatial component obtained through application of a linear invertible transform; and

one or more processors configured to:

perform psychoacoustic audio decoding with respect to the encoded foreground audio signal to obtain a foreground audio signal;

determine, when performing the psychoacoustic audio decoding with respect to the encoded foreground audio signal, a first bit allocation for the encoded foreground audio signal;

determine, based on the first bit allocation for the encoded foreground audio signal, a second bit allocation for the quantized spatial component, wherein, to determine the second bit allocation, the one or more processors are configured to:

obtain, from the bitstream, a number of bits allocated to a course quantized gain and each of one or more fine quantized residuals, the course quantized gain and the one or more fine quantized residual represent a gain of the foreground audio signal; and

determine, based on the number of bits allocated to the course quantized gain and each of the one or more fine quantized residuals, the second bit allocation;

dequantize, based on the second bit allocation for the quantized spatial component, the quantized spatial component to obtain a spatial component; and

reconstruct, based on the foreground audio signal and the spatial component, the scene-based audio data.

13. The device of claim 12 , wherein the one or more processors are configured to perform the psychoacoustic audio decoding according to a decompression algorithm with respect to the encoded foreground audio signal to obtain the foreground audio signal.

14. The device of claim 12 , wherein the one or more processors are configured to:

determine a spectral perceptual importance of the encoded foreground audio signal relative to a soundfield represented by the scene-based audio data; and

determine, based on the spectral perceptual importance, the first bit allocation.

15. The device of claim 14 , wherein the one or more processors are configured to:

determine, based on the spectral perceptual importance and the number of bits allocated to the course quantized gain, a static spatial bit distribution;

determine, based on the number of bits allocated to each of the one or more fine quantized residuals, a dynamic spatial bit distribution; and

determine, based on the static spatial bit distribution and the dynamic spatial bit distribution, the second bit allocation.

16. The device of claim 12 , wherein the scene-based audio data comprises ambisonic coefficients corresponding to an order greater than one.

17. The device of claim 12 , wherein the scene-based audio data comprises audio data defined in a spherical harmonic domain.

18. The device of claim 17 ,

wherein the foreground audio signal comprises a foreground audio signal defined in the spherical harmonic domain, and

wherein the spatial component comprises a spatial component defined in the spherical harmonic domain.

19. The device of claim 12 , wherein the one or more processors are further configured to:

render the scene-based audio data to one or more speaker feeds; and

reproduce, based on the speaker feeds, a soundfield represented by the scene-based audio data.

20. The device of claim 12 ,

wherein the one or more processors are further configured to render the scene-based audio data to one or more speaker feeds, and

wherein the device comprises one or more speakers configured to reproduce, based on the speaker feeds, a soundfield represented by the scene-based audio data.

21. The device of claim 12 , wherein the scene-based audio data includes mixed-order ambisonic audio data.

22. The device of claim 12 , wherein the one or more processors are further configured to:

render the scene-based audio data to one or more speaker feeds; and

output the speaker feeds to one or more speakers to reproduce, based on the speaker feeds, a soundfield represented by the scene-based audio data.

23. A method of decoding a bitstream representative of scene-based audio data, the method comprising:

obtaining, from the bitstream, an encoded foreground audio signal and a corresponding quantized spatial component that defines the spatial characteristics of the encoded foreground audio signal, the encoded foreground audio signal and the corresponding spatial component obtained through application of a linear invertible transform;

performing psychoacoustic audio decoding with respect to the encoded foreground audio signal to obtain a foreground audio signal;

determining, when performing psychoacoustic audio decoding with respect to the encoded foreground audio signal, a first bit allocation for the encoded foreground audio signal;

determining, based on the first bit allocation for the encoded foreground audio signal, a second bit allocation for the quantized spatial component, wherein determining the second bit allocation comprises:

obtaining, from the bitstream, a number of bits allocated to a course quantized gain and each of one or more fine quantized residuals, the course quantized gain and the one or more fine quantized residual represent a gain of the foreground audio signal; and

determining, based on the number of bits allocated to the course quantized gain and each of the one or more fine quantized residuals, the second bit allocation;

dequantizing, based on the second bit allocation for the quantized spatial component, the quantized spatial component to obtain a spatial component; and

reconstructing, based on the foreground audio signal and the spatial component, the scene-based audio data.