Advanced quantizer
First Claim
1. A quantization system configured to quantize a first coefficient of a block of coefficients derived from an audio signal;
- wherein the block of coefficients comprises a plurality of coefficients for a plurality of corresponding frequency bins;
wherein the quantization system is configured to encode audio data based on the first coefficient by;
providing a set of quantizers;
wherein the set of quantizers comprises a limited number of different quantizers yielding different signal-to-noise ratios, referred to as SNR, respectively;
wherein the different quantizers of the set of quantizers are ordered according to their SNR;
the set of quantizers including a noise-filling quantizer;
wherein the noise-filling quantizer is configured to quantize the first coefficient by replacing a value of the first coefficient with a random value generated according to a pre-determined statistical model;
wherein the noise-filling quantizer is used for a zero bit-rate situation;
one or more dithered quantizers; and
one or more un-dithered deterministic quantizers;
determining an SNR indication indicative of an SNR attributed to the first coefficient;
selecting a first quantizer yielding a particular SNR from the set of quantizers, based on the SNR indication; and
quantizing the first coefficient using the first quantizer;
wherein the quantization system includes one or more processors comprised in on or more computing devices to encode the audio data based upon the first coefficient.
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Abstract
The present document relates an audio encoding and decoding system (referred to as an audio codec system). In particular, the present document relates to a transform-based audio codec system which is particularly well suited for voice encoding/decoding. A quantization unit configured to quantize a first coefficient of a block of coefficients is described. The block of coefficients comprises a plurality of coefficients for a plurality of corresponding frequency bins. The quantization unit is configured to provide a set of quantizers. The set of quantizers comprises a plurality of different quantizers associated with a plurality of different signal-to-noise ratios, referred to as SNR, respectively. The plurality of different quantizers includes a noise-filling quantizer; one or more dithered quantizers; and one or more un-dithered quantizers. The quantization unit is further configured to determine an SNR indication indicative of a SNR attributed to the first coefficient, and to select a first quantizer from the set of quantizers, based on the SNR indication. In addition, the quantization unit is configured to quantize the first coefficient using the first quantizer.
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Citations
14 Claims
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1. A quantization system configured to quantize a first coefficient of a block of coefficients derived from an audio signal;
- wherein the block of coefficients comprises a plurality of coefficients for a plurality of corresponding frequency bins;
wherein the quantization system is configured to encode audio data based on the first coefficient by;providing a set of quantizers; wherein the set of quantizers comprises a limited number of different quantizers yielding different signal-to-noise ratios, referred to as SNR, respectively; wherein the different quantizers of the set of quantizers are ordered according to their SNR; the set of quantizers including a noise-filling quantizer; wherein the noise-filling quantizer is configured to quantize the first coefficient by replacing a value of the first coefficient with a random value generated according to a pre-determined statistical model;
wherein the noise-filling quantizer is used for a zero bit-rate situation;one or more dithered quantizers; and one or more un-dithered deterministic quantizers; determining an SNR indication indicative of an SNR attributed to the first coefficient; selecting a first quantizer yielding a particular SNR from the set of quantizers, based on the SNR indication; and quantizing the first coefficient using the first quantizer; wherein the quantization system includes one or more processors comprised in on or more computing devices to encode the audio data based upon the first coefficient. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
- wherein the block of coefficients comprises a plurality of coefficients for a plurality of corresponding frequency bins;
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12. An inverse quantization system configured to de-quantize quantization indices;
- wherein the quantization indices are associated with a block of coefficients comprising a plurality of coefficients for a plurality of corresponding frequency bins;
wherein the block of coefficients is derived from an audio signal;
wherein the inverse quantization system is configured to decode audio data based upon first coefficient by;providing a set of quantizers;
wherein the set of quantizers comprises a limited number of different quantizers yielding different signal-to-noise ratios, referred to as SNR, respectively;wherein the different quantizers of the set of quantizers are ordered according to their SNR; the set of quantizers including a noise-filling quantizer; wherein the noise-filling quantizer is configured to quantize a coefficient by replacing a value of the coefficient with a random value generated according to a pre-determined statistical model;
wherein the noise-filling quantizer is used for a zero bit-rate situation;one or more dithered quantizers; and one or more un-dithered deterministic quantizers; determining an SNR indication indicative of an SNR attributed to a first coefficient from the block of coefficients; selecting a first quantizer yielding a particular SNR from the set of quantizers, based on the SNR indication; and determining a first quantized coefficient for the first coefficient using the first quantizer; wherein the inverse quantization system includes one or more processors comprised in one or more computing devices to decode the audio data based upon first coefficient.
- wherein the quantization indices are associated with a block of coefficients comprising a plurality of coefficients for a plurality of corresponding frequency bins;
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13. A method for quantizing a first coefficient of a block of coefficients derived from an audio signal;
- wherein the block of coefficients comprises a plurality of coefficients for a plurality of corresponding frequency bins to encode audio data based upon first coefficient;
wherein the method comprisesa. providing a set of quantizers;
wherein the set of quantizers comprises a plurality of different quantizers associated with a plurality of different signal-to-noise ratios, referred to as SNR, respectively, the plurality of different quantizers includingi. a noise-filling quantizer;
wherein the noise-filling quantizer is configured to quantize the first coefficient by replacing a value of the first coefficient with a random value generated according to a pre-determined statistical model;
wherein the noise-filling quantizer is used for a zero bit-rate situation;ii. one or more dithered quantizers; and iii. one or more un-dithered deterministic quantizers; b. determining an SNR indication indicative of a SNR attributed to the first coefficient; c. selecting a first quantizer from the set of quantizers, based on the SNR indication; and d. quantizing the first coefficient using the first quantizer, wherein the method is performed by one or more processors comprised in one or more computing devices to encode the audio data based upon first coefficient.
- wherein the block of coefficients comprises a plurality of coefficients for a plurality of corresponding frequency bins to encode audio data based upon first coefficient;
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14. A method for de-quantizing quantization indices for decoding audio data based upon first coefficient;
- wherein the quantization indices are associated with a block of coefficients comprising a plurality of coefficients for a plurality of corresponding frequency bins;
wherein the block of coefficients is derived from an audio signal;
wherein the method comprisesa. providing a set of quantizers;
wherein the set of quantizers comprises a plurality of different quantizers associated with a plurality of different signal-to-noise ratios, referred to as SNR, respectively, the plurality of different quantizers includingi. a noise-filling quantizer;
wherein the noise-filling quantizer is configured to quantize a coefficient by replacing a value of the coefficient with a random value generated according to a pre-determined statistical model;
wherein the noise-filling quantizer is used for a zero bit-rate situation;ii. one or more dithered quantizers; and iii. one or more un-dithered deterministic quantizers; b. determining an SNR indication indicative of a SNR attributed to a first coefficient from the block of coefficients; c. selecting a first quantizer yielding a particular SNR from the set of quantizers, based on the SNR indication; and d. determining a first quantized coefficient for the first coefficient using the first quantizer, wherein the method is performed by one or more processors comprised in one or more computing devices for decoding the audio data based upon first coefficient.
- wherein the quantization indices are associated with a block of coefficients comprising a plurality of coefficients for a plurality of corresponding frequency bins;
Specification