Higher Order Ambisonics Encoding And Decoding
AssigneeApple Inc.
InventorsMoo Young Kim, Sina Zamani, Dipanjan Sen
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Abstract
Encoding and decoding of higher order ambisonics, HOA, data for purposes of bitrate reduction. One aspect uses principal components analysis to produce spatial descriptors. Other aspects include various spatial descriptor quantization techniques.
Claims12
A method for encoding higher order ambisonics, HOA, data by varying sub-band bandwidth as a function of SD index and SB index, the method comprising:
- analyzing an input HOA matrix to produce a first SD group that comprises a plurality of first SD components, wherein the plurality of first SD components cover a plurality of first sub-bands, respectively, and a second SD group that comprises a plurality of second SD components, wherein the plurality of second SD components cover a plurality of second sub-bands, respectively, wherein each of the plurality of second sub-bands has a different bandwidth than each of the plurality of first sub-bands;
- and
- formatting the first SD group and the second SD group into an encoded audio content bitstream.
A method for decoding higher order ambisonics, HOA, data that has been encoded with a variable number of spatial descriptor, SD, components in each SD group, the method comprising:
- extracting, from an encoded audio content bitstream, spatial descriptor, SD, groups and corresponding salient components of higher order ambisonics, HOA, wherein the SD groups and the corresponding salient components are in a frequency domain that spans at least a plurality of sub-bands, and wherein the encoded audio content bitstream supports a format in which a total number of one or more SD components in each SD group can vary as a function of SD group, and in which bandwidth of each of the one more SD components in a first SD group is different than bandwidth of each of the one or more SD components in a second SD group;
- and
- computing an HOA matrix using the SD groups and corresponding salient components.
A method for decoding HOA data in which HOA order varies per SD group, the method comprising:
- a. extracting, from an encoded audio content bitstream, spatial descriptor, SD, groups and corresponding salient components of higher order ambisonics, HOA, wherein the SD groups and the corresponding salient components are in a frequency domain that spans at least a plurality of sub-bands, and wherein the encoded audio content bitstream supports a format in which HOA order of each SD group can vary as a function of SD group;
- and
- b. computing an HOA matrix using the SD groups and corresponding salient components.
Dependencies are inferred from the claim text.