Audio encoding and rendering with discontinuity compensation

1. A method for generating an encoded audio program, including steps of:

(a) encoding N audio input signals as N channels of encoded audio content, in accordance with a sequence of rendering matrices specified for rendering audio content of at least some of the N audio input signals, where transitions between matrices of the sequence of rendering matrices occur at update times;

(b) determining an unscaled correction signal set and correction scaling coefficients for scaling the correction signal set, for correcting a discontinuity in audio rendered from the encoded audio program resulting from an update of the rendering matrices, wherein the unscaled correction signal set comprises at least one of a zeroth order correction signal p 0 (t) for correcting a zeroth order discontinuity, being a discontinuity in the rendering matrix itself at the time of the update, and a first order correction signal p 1 (t) for correcting a first order discontinuity, being a discontinuity in the derivative of the rendering matrix at the time of the update; and

(c) generating the encoded audio program to include N channels of discontinuity-corrected, encoded audio content, by adding the correction signal set, scaled by the correction scaling coefficients, to the encoded audio content of at least some of the N channels, wherein step (c) also includes a step of including the correction signal set in the encoded audio program.

2. The method of claim 1 , wherein both step (a), and step (c) are implemented by performance of a matrix multiplication on a vector whose elements are a sequence of the N audio input signals and the correction signal set.

3. The method of claim 1 , wherein each correction signal of the correction signal set is included as one of the channels of the encoded audio program.

4. The method of claim 1 , wherein the sequence of rendering matrices has been specified for rendering at least one mix of audio content of at least some of the N audio input signals, the sequence of rendering matrices determines a sequence of input rendering matrices to be applied by an encoder, and at least one sequence of output rendering matrices to be applied by a decoder.

5. The method of claim 4 , wherein the correction scaling coefficients with the sequence of input rendering matrices determine a sequence of augmented input rendering matrices, and step (c) includes a step of applying the augmented input rendering matrices to the N input signals and the correction signal set.

6. The method of claim 1 , wherein the audio input signals are indicative of audio objects.

7. A decoder, including:

a memory which stores, in non-transient manner, at least one segment of an encoded audio program which includes N channels of discontinuity-corrected, encoded audio content, and includes data indicative of an output rendering matrix; and

a mix generation subsystem coupled and configured to mix samples of the discontinuity-corrected, encoded audio content, including by applying to the samples said data indicative of the output rendering matrix, to generate an M-channel mix of at least some of the discontinuity-corrected, encoded audio content, where a sequence of rendering matrices has been specified for rendering the M-channel mix, where transitions between matrices of the sequence of rendering matrices occur at update times, where N and M are integers, and wherein the N channels of discontinuity-corrected, encoded audio content have been generated by applying discontinuity correction values to N channels of audio content to implement discontinuity correction at at least one of the update times.

8. The decoder of claim 7 , wherein N≥M.

9. The decoder of claim 7 , wherein the encoded audio program includes data indicative of at least some of the discontinuity correction values, the output rendering matrix is an augmented version of an M×M matrix, and the mix generation subsystem is configured to mix the samples including by applying to said samples, and to at least some of the discontinuity correction values, said data indicative of the output rendering matrix.

10. The decoder of claim 7 , wherein the N channels of audio content are indicative of N audio objects, and the M-channel mix is a discontinuity-corrected mix of audio object content.

11. An audio encoder configured to generate an encoded audio program, said encoder including:

a first subsystem coupled and configured to encode N audio input signals as N channels of encoded audio content, in accordance with a sequence of rendering matrices specified for rendering audio content of at least some of the N audio input signals, where transitions between matrices of the sequence of rendering matrices occur at update times; and

a second subsystem, coupled to the first subsystem, and configured to determine an unscaled correction signal set and correction scaling coefficients for scaling the correction signal set, for correcting a discontinuity in audio rendered from the encoded audio program resulting from an update of the rendering matrices, wherein the unscaled correction signal set comprises at least one of a zeroth order correction signal p 0 (t) for correction a zeroth order discontinuity, being a discontinuity in the rendering matrix itself at the time of the update, and a first order correction signal p 1 (t) for correcting a first order discontinuity, being a discontinuity in the derivative of the rendering matrix at the time of the update,

wherein the first subsystem is configured to generate the encoded audio program to include N channels of discontinuity-corrected, encoded audio content, by adding the correction signal set, scaled by the correction scaling coefficients to the encoded audio content of at least some of the N channels

wherein the encoder is further configured to include the correction signal set in the encoded audio program.

12. The encoder of claim 11 , wherein the first subsystem is configured to encode the N audio input signals as the N channels of encoded audio content, and to generate the encoded audio program by performing a matrix multiplication on a vector whose elements are a sequence of the N audio input signals and the correction signal set.

13. The method of claim 4 , further comprising including, in the encoded audio program, the at least one sequence of output rendering matrices to be applied by a decoder.

14. The method of claim 4 , wherein the sequence of rendering matrices determines a plurality of sequences of output rendering matrices to be applied by a decoder.

15. The method of claim 4 , wherein the at least one sequence of output rendering matrices to be applied by a decoder comprises a sequence of M×M output rendering matrices to be applied to an M-channel subset of the N channels of discontinuity-corrected, encoded audio content to generate an M-channel mix of the N audio input signals.

16. The method of claim 15 , wherein the N audio input signals are indicative of N audio objects, and the M-channel mix is a discontinuity-corrected mix of audio object content.

17. The method of claim 4 , wherein the at least one sequence of output rendering matrices to be applied by a decoder comprises a sequence of (N+1)×(N+1) output rendering matrices to be applied to the N channels of discontinuity-corrected, encoded audio content and the correction signal set to losslessly reconstruct the N audio input signals.

18. The decoder of claim 7 , wherein N =M, and the M-channel mix of at least some of the discontinuity-corrected, encoded audio content is a lossless reconstruction of the N channels of audio content.

19. The decoder of claim 18 , wherein the encoded audio program includes data indicative of at least some of the discontinuity correction values, the data indicative of the output rendering matrix corresponds to coefficients of a sequence of (N+1)×(N+1) matrices, and the lossless reconstruction of the N channels of audio content is generated by applying the sequence of (N+1)×(N+1) matrices to the samples of the discontinuity-corrected, encoded audio content and to at least some of the discontinuity correction values.

20. The decoder of claim 7 , wherein M is less than N, the data indicative of the output rendering matrix corresponds to coefficients of a sequence of M×M matrices, and generating the M-channel mix comprises applying the sequence of M×M matrices to samples of an M-channel subset of the N channels of discontinuity-corrected, encoded audio content.