Identifying sources from which higher order ambisonic audio data is generated

Patent metadata

Field	Value
Publication number	US-9495968-B2
Application number	US-201414289174-A
Country	US
Kind code	B2
Filing date	May 28, 2014
Priority date	May 29, 2013
Publication date	Nov 15, 2016
Grant date	Nov 15, 2016

Abstract

In general, techniques are described for obtaining an indication of whether spherical harmonic coefficients are representative of a synthetic audio object. In accordance with the techniques, a device comprising one or more processors may be configured to obtain an indication of whether spherical harmonic coefficients representative of a sound field are generated from a synthetic audio object.

First claim

The invention claimed is:

1. A method comprising:
selecting one of a plurality of decompression schemes based on an indication of whether a compressed version of spherical harmonic coefficients representative of a sound field are generated from a synthetic audio object, wherein the compressed version of the spherical harmonic coefficients includes one or more vectors defined in the spherical harmonic domain and decomposed from the plurality of spherical harmonic coefficients,
wherein the indication is obtained by at least in part:
excluding a first vector from a framed spherical harmonic coefficient matrix storing at least a portion of the spherical harmonic coefficients representative of the sound field to obtain a reduced framed spherical harmonic coefficient matrix;
predicting a vector of the reduced framed spherical harmonic coefficient matrix based, at least in part, on a sum of remaining vectors of the reduced framed spherical harmonic coefficient matrix;
computing an error based on the predicted vector and the corresponding vector of the framed spherical harmonic coefficient matrix;
computing a ratio based on an energy of the corresponding vector of the framed spherical harmonic coefficient matrix and the error; and
comparing the ratio to a threshold to determine whether the spherical harmonic coefficients representative of the sound field are generated from the synthetic audio object;

decompressing the compressed version of the spherical harmonic coefficients using the selected one of the plurality of decompression schemes to obtain a decompressed version of the spherical harmonic coefficients;
rendering the decompressed version of the spherical harmonic coefficients to obtain speaker feeds; and
outputting the speaker feeds to drive loudspeakers such that the loudspeakers reproduce the soundfield.

2. The method of claim 1 ,
wherein selecting one of the plurality of decompression schemes comprises selecting the one of the plurality of decompression schemes with an integrated decoder, and
wherein decompressing the compressed version of the spherical harmonic coefficients comprises decompressing the compressed version of the spherical harmonic coefficients with the integrated decoder.

3. A device comprising:
a memory configured to store a compressed version of spherical harmonic coefficients representative of a sound field; and
one or more processors configured to select one of a plurality of decompression schemes based on an indication of whether the compressed version of the spherical harmonic coefficients are generated from a synthetic audio object, wherein the compressed version of the spherical harmonic coefficients includes one or more vectors defined in the spherical harmonic domain and decomposed from the plurality of spherical harmonic coefficients, decompress the compressed version of the spherical harmonic coefficients using the selected one of the plurality of decompression schemes to obtain a decompressed version of the spherical harmonic coefficients, render the decompressed version of the spherical harmonic coefficients to obtain speaker feeds, and output the speaker feeds to drive loudspeakers such that the loudspeakers reproduce the soundfield,
wherein the indication is obtained by at least in part:
excluding a first vector from a framed spherical harmonic coefficient matrix storing at least a portion of the spherical harmonic coefficients representative of the sound field to obtain a reduced framed spherical harmonic coefficient matrix;
predicting a vector of the reduced framed spherical harmonic coefficient matrix based, at least in part, on a sum of remaining vectors of the reduced framed spherical harmonic coefficient matrix;
computing an error based on the predicted vector and the corresponding vector of the framed spherical harmonic coefficient matrix;
computing a ratio based on an energy of the corresponding vector of the framed spherical harmonic coefficient matrix and the error; and
comparing the ratio to a threshold to determine whether the spherical harmonic coefficients representative of the sound field are generated from the synthetic audio object.

4. The device of claim 3 , wherein the device comprises an integrated decoder.

5. The method of claim 1 ,
wherein the method is performed by a device comprising one or more loudspeakers, and
wherein the method further comprises:
rendering the spherical harmonic coefficients to obtain loudspeaker feeds; and
outputting the loudspeaker feeds to drive the one or more loudspeakers.

6. The device of claim 3 , further comprising one or more loudspeakers,
wherein the one or more processors are further configured to:
render the spherical harmonic coefficient to obtain loudspeaker feeds; and
output the loudspeaker feeds to drive the one or more loudspeakers.

7. A device comprising:
means for selecting one of a plurality of decompression schemes based on an indication of whether a compressed version of spherical harmonic coefficients representative of a sound field are generated from a synthetic audio object, wherein the compressed version of the spherical harmonic coefficients includes one or more vectors defined in the spherical harmonic domain and decomposed from the plurality of spherical harmonic coefficients,
wherein the indication is obtained by at least in part:
excluding a first vector from a framed spherical harmonic coefficient matrix storing at least a portion of the spherical harmonic coefficients representative of the sound field to obtain a reduced framed spherical harmonic coefficient matrix;
predicting a vector of the reduced framed spherical harmonic coefficient matrix based, at least in part, on a sum of remaining vectors of the reduced framed spherical harmonic coefficient matrix;
computing an error based on the predicted vector and the corresponding vector of the framed spherical harmonic coefficient matrix;
computing a ratio based on an energy of the corresponding vector of the framed spherical harmonic coefficient matrix and the error; and
comparing the ratio to a threshold to determine whether the spherical harmonic coefficients representative of the sound field are generated from the synthetic audio object;

means for decompressing the compressed version of the spherical harmonic coefficients using the selected one of the plurality of decompression schemes to obtain a decompressed version of the spherical harmonic coefficients;
means for rendering the decompressed version of the spherical harmonic coefficients to obtain speaker feeds; and
means for outputting the speaker feeds to drive loudspeakers such that the loudspeakers reproduce the soundfield.

8. The device of claim 7 ,
wherein the means for selecting one of the plurality of decompression schemes comprises an integrated decoder, and
wherein the means for decompressing the compressed version of the spherical harmonic coefficients comprises the integrated decoder.

9. A non-transitory computer-readable storage medium having stored thereon instructions that, when executed, cause one or more processors of an integrated decoding device to:
select one of a plurality of decompression schemes based on an indication of whether a compressed version of spherical harmonic coefficients representative of a sound field are generated from a synthetic audio object, wherein the compressed version of the spherical harmonic coefficients includes one or more vectors defined in the spherical harmonic domain and decomposed from the plurality of spherical harmonic coefficients,
wherein the indication is obtained by at least in part:
excluding a first vector from a framed spherical harmonic coefficient matrix storing at least a portion of the spherical harmoni

Assignees

• Qualcomm Inc

Inventors

• Sen Dipanjan
• Morrell Martin James
• Peters Nils Günther

Classifications

• H04S7/30

  Control circuits for electronic adaptation of the sound field · CPC title

• H04S2420/11

  Application of ambisonics in stereophonic audio systems · CPC title

• H04S5/005 Primary

  of the pseudo five- or more-channel type, e.g. virtual surround · CPC title

• H04S2420/01

  Enhancing the perception of the sound image or of the spatial distribution using head related transfer functions [HRTF's] or equivalents thereof, e.g. interaural time difference [ITD] or interaural level difference [ILD] · CPC title

• G10L19/06

  Determination or coding of the spectral characteristics, e.g. of the short-term prediction coefficients · CPC title