Low-complexity encoding/decoding of quantized MDCT spectrum in scalable speech and audio codecs

A scalable speech and audio encoder device, comprising:

• a Code Excited Linear Prediction (CELP)-based encoding layer module adapted to produce a residual signal, where the residual signal is a difference between an original audio signal and a reconstructed version of the original audio signal;
• a Discrete Cosine Transform (DCT)-type transform layer module adapted to
• obtain a residual signal from the Code Excited Linear Prediction (CELP)-based encoding layer module, wherein the CELP-based encoding layer module comprises a CELP-based encoding layer having one or two previous layers scalable speech and audio codec;
• and
• transform the residual signal, from a previous layer, at a Discrete Cosine Transform (DCT)-type transform layer to obtain a corresponding transform spectrum having a plurality of spectral lines;
• and
• a sub-band generator adapted to split the plurality of spectral lines into a plurality of sub-bands;
• and
• a region generator adapted to group consecutive sub-bands into regions;
• and
• a sub-pulse encoder adapted to encode positions of a selected subset of spectral lines within a region based on representing spectral line positions using the combinatorial position coding technique for non-zero spectral lines positions.

A scalable speech and audio encoder device, comprising:

• means for obtaining a residual signal from a Code Excited Linear Prediction (CELP)-based encoding layer, wherein the CELP-based encoding layer comprises one or two previous layers in a scalable speech and audio codec, where the residual signal is a difference between an original audio signal and a reconstructed version of the original audio signal;
• means for transforming the residual signal, from a previous layer, at a Discrete Cosine Transform (DCT)-type transform layer to obtain a corresponding transform spectrum having a plurality of spectral lines;
• and
• means for splitting the plurality of spectral lines into a plurality of sub-bands;
• and
• means for grouping consecutive sub-bands into regions;
• and
• means for encoding positions of a selected subset of spectral lines within a region based on representing spectral line positions using the combinatorial position coding technique for non-zero spectral lines positions.

A processor including a scalable speech and audio encoding circuit adapted to:

• obtain a residual signal from a Code Excited Linear Prediction (CELP)-based encoding layer, wherein the CELP-based encoding layer comprises one or two previous layers in a scalable speech and audio codec, where the residual signal is a difference between an original audio signal and a reconstructed version of the original audio signal;
• transform the residual signal, from a previous layer, at a Discrete Cosine Transform (DCT)-type transform layer to obtain a corresponding transform spectrum having a plurality of spectral lines;
• and
• split the plurality of spectral lines into a plurality of sub-bands;
• and
• group consecutive sub-bands into regions;
• and
• encode positions of a selected subset of spectral lines within a region based on representing spectral line positions using the combinatorial position coding technique for non-zero spectral lines positions.

A non-transitory machine-readable medium comprising instructions operational for scalable speech and audio encoding, which when executed by one or more processors causes the processors to:

• obtain a residual signal from a Code Excited Linear Prediction (CELP)-based encoding layer, wherein the CELP-based encoding layer comprises one or two previous layers in a scalable speech and audio codec, where the residual signal is a difference between an original audio signal and a reconstructed version of the original audio signal;
• transform the residual signal, from a previous layer, at a Discrete Cosine Transform (DCT)-type transform layer to obtain a corresponding transform spectrum having a plurality of spectral lines;
• and
• split the plurality of spectral lines into a plurality of sub-bands;
• and
• group consecutive sub-bands into regions;
• and
• encode positions of a selected subset of spectral lines within a region based on representing spectral line positions using the combinatorial position coding technique for non-zero spectral lines positions.

A method for decoding in a scalable speech and audio codec having multiple layers, comprising:

• obtaining an index representing a plurality of transform spectrum spectral lines of a residual signal, where the residual signal is a difference between an original audio signal and a reconstructed version of the original audio signal from a Code Excited Linear Prediction (CELP)-based encoding layer, wherein the CELP-based encoding layer comprises one or two previous layers in a scalable speech and audio codec;
• decoding the index, in a higher layer, by reversing a combinatorial position coding technique used to encode the plurality of transform spectrum spectral lines;
• and
• decoding positions of a selected subset of spectral lines based on representing spectral line positions using the combinatorial position coding technique for non-zero spectral lines positions;
• and
• synthesizing a version of the residual signal using the decoded plurality of transform spectrum spectral lines at an Inverse Discrete Cosine Transform (IDCT)-type inverse transform layer.

A scalable speech and audio decoder device, comprising:

• a combinatorial spectrum decoder adapted to
• obtain an index representing a plurality of transform spectrum spectral lines of a residual signal, where the residual signal is a difference between an original audio signal and a reconstructed version of the original audio signal from a Code Excited Linear Prediction (CELP)-based encoding layer module, wherein the CELP-based encoding layer module comprises a CELP-based encoding layer having one or two previous layers in a scalable speech and audio codec;
• decode the index, in a higher layer, by reversing a combinatorial position coding technique used to encode the plurality of transform spectrum spectral lines;
• and
• decode positions of a selected subset of spectral lines based on representing spectral line positions using the combinatorial position coding technique for non-zero spectral lines positions;
• and
• an Inverse Discrete Cosine Transform (IDCT)-type inverse transform layer module adapted to synthesize a version of the residual signal using the decoded plurality of transform spectrum spectral lines.

A scalable speech and audio decoder device, comprising:

• means for obtaining an index representing a plurality of transform spectrum spectral lines of a residual signal, where the residual signal is a difference between an original audio signal and a reconstructed version of the original audio signal from a Code Excited Linear Prediction (CELP)-based encoding layer, wherein the CELP-based encoding layer comprises one or two previous layers in a scalable speech and audio codec;
• means for decoding the index, in a higher layer, by reversing a combinatorial position coding technique used to encode the plurality of transform spectrum spectral lines;
• and
• means for decoding positions of a selected subset of spectral lines based on representing spectral line positions using the combinatorial position coding technique for non-zero spectral lines positions;
• and
• means for synthesizing a version of the residual signal using the decoded plurality of transform spectrum spectral lines at an Inverse Discrete Cosine Transform (IDCT)-type inverse transform layer.

A processor including a scalable speech and audio decoding circuit adapted to:

• obtain an index representing a plurality of transform spectrum spectral lines of a residual signal, where the residual signal is a difference between an original audio signal and a reconstructed version of the original audio signal from a Code Excited Linear Prediction (CELP)-based encoding layer, wherein the CELP-based encoding layer comprises one or two previous layers in a scalable speech and audio codec;
• decode the index, at a higher layer, by reversing a combinatorial position coding technique used to encode the plurality of transform spectrum spectral lines;
• and
• decode positions of a selected subset of spectral lines based on representing spectral line positions using the combinatorial position coding technique for non-zero spectral lines positions;
• and
• synthesize a version of the residual signal using the decoded plurality of transform spectrum spectral lines at an Inverse Discrete Cosine Transform (IDCT)-type inverse transform layer.

A non-transitory machine-readable medium comprising instructions operational for scalable speech and audio decoding, which when executed by one or more processors causes the processors to:

• obtain an index representing a plurality of transform spectrum spectral lines of a residual signal, where the residual signal is a difference between an original audio signal and a reconstructed version of the original audio signal from a Code Excited Linear Prediction (CELP)-based encoding layer, wherein the CELP-based encoding layer comprises one or two previous layers in a scalable speech and audio codec;
• decode the index, at a higher layer, by reversing a combinatorial position coding technique used to encode the plurality of transform spectrum spectral lines;
• and
• decode positions of a selected subset of spectral lines based on representing spectral line positions using the combinatorial position coding technique for non-zero spectral lines positions;
• and
• synthesize a version of the residual signal using the decoded plurality of transform spectrum spectral lines at an Inverse Discrete Cosine Transform (IDCT)-type inverse transform layer.