Higher order ambisonics signal compression
Systems and techniques for compression and decoding of audio data are generally disclosed. An example device for compressing higher order ambisonic (HOA) coefficients representative of a soundfield includes a memory configured to store audio data and one or more processors configured to: determine when to use ambient HOA coefficients of the HOA coefficients to augment one or more foreground audio objects obtained through decomposition of the HOA coefficients based on one or more singular values also obtained through the decomposition of the HOA coefficients, the ambient HOA coefficients representative of an ambient component of the soundfield.
1. A device for decoding encoded higher order ambisonics (HOA) coefficients representative of a soundfield, the device comprising:
a memory configured to store the encoded HOA coefficients representative of the soundfield; and
one or more processors, when configured to decode the encoded HOA coefficients stored in the memory, being configured to:
receive, as part of an encoded bitstream including the encoded HOA coefficients, an audio object representative of the encoded HOA coefficients;
receive bit-allocation metadata indicative of an allocation of a number of bits of the encoded bitstream to the audio object of the soundfield;
extract, based on the bit-allocation metadata, the number of bits from the encoded bitstream to parse the audio object from the encoded bitstream;
render, based on the audio object, one or more speaker feeds; and
output the one or more speaker feeds to one or more speakers.
2. The device of claim 1 , wherein the bit-allocation metadata further includes an upper limit on a number of bits that can be allocated to any single audio object of a plurality of audio objects representative of the soundfield.
3. The device of claim 1 , wherein the one or more processors are further configured to allocate the bits such that no audio object of the soundfield is allocated a respective number of bits that exceeds a maximum number of bits.
4. A method of decoding encoded higher order ambisonics (HOA) coefficients representative of a soundfield, the method comprising:
receiving, as part of an encoded bitstream including the encoded HOA coefficients, an audio object representative of the encoded HOA coefficients;
receiving bit-allocation metadata indicative of an allocation of a number of bits of the encoded bitstream to the audio object of the soundfield;
extracting, based on the bit-allocation metadata, the number of bits from the encoded bitstream to parse the audio object from the encoded bitstream;
rendering, based on the audio object, one or more speaker feeds; and
outputting the one or more speaker feeds to one or more speakers.
5. The method of claim 4 , wherein the bit-allocation metadata further includes an upper limit on a number of bits that can be allocated to any single audio object of a plurality of audio objects representative of the soundfield.
6. The method of claim 4 , further comprising allocating the bits such that no audio object of the soundfield is allocated a respective number of bits that exceeds a maximum number of bits.
7. A device for decoding encoded higher order ambisonics (HOA) coefficients representative of a soundfield, the device comprising:
means for receiving, as part of an encoded bitstream including the encoded HOA coefficients, an audio object representative of the encoded HOA coefficients;
means for receiving bit-allocation metadata indicative of an allocation of a number of bits of the encoded bitstream to the audio object of the soundfield;
means for extracting, based on the bit-allocation metadata, the number of bits from the encoded bitstream to parse the audio object from the encoded bitstream;
means for rendering, based on the audio object, one or more speaker feeds; and
means for outputting the one or more speaker feeds to one or more speakers.
8. The device of claim 7 , wherein the bit-allocation metadata further includes an upper limit on a number of bits that can be allocated to any single audio object of a plurality of audio objects representative of the soundfield.
9. The device of claim 7 , further comprising means for allocating the bits such that no audio object of the soundfield is allocated a respective number of bits that exceeds a maximum number of bits.
10. A non-transitory computer-readable storage medium encoded with instructions that, when executed, cause a processor of a device for decoding encoded higher order ambisonics (HOA) coefficients representative of a soundfield to:
receive, as part of an encoded bitstream including the encoded HOA coefficients, an audio object representative of the encoded HOA coefficients;
receive bit-allocation metadata indicative of an allocation of a number of bits of the encoded bitstream to the audio object of the soundfield;
extract, based on the bit-allocation metadata, the number of bits from the encoded bitstream to parse the audio object from the encoded bitstream;
render, based on the audio object, one or more speaker feeds; and
output the one or more speaker feeds to one or more speakers.
11. The non-transitory computer-readable storage medium of claim 10 , wherein the bit-allocation metadata further includes an upper limit on a number of bits that can be allocated to any single audio object of a plurality of audio objects representative of the soundfield.
12. The non-transitory computer-readable storage medium of claim 10 , further encoded with instructions that, when executed, cause the processor to allocate the bits such that no audio object of the soundfield is allocated a respective number of bits that exceeds a maximum number of bits.