Method and device for robust predictive vector quantization of linear prediction parameters in variable bit rate speech coding
First Claim
1. Apparatus comprising a switched predictive vector quantizer having an input for receiving an input Linear Prediction (LP) parameter vector z and a first processor for removing a vector of mean LP parameters μ
- from the input LP parameter vector z to produce a mean-removed LP parameter vector x, a second processor for determining a prediction vector p and a third processor for removing the prediction vector p from the mean-removed LP parameter vector x to produce a prediction error vector e, further comprising a fourth processor responsive to frame classification information such that if a frame corresponding to the input LP parameter vector z is stationary voiced then autoregressive (AR) prediction is used and the error vector e is scaled by a certain factor to obtain a scaled prediction error vector e′
, whereas if the frame is not stationary voiced moving average (MA) prediction is used and the scaling factor is equal to one;
further comprising a fifth processor coupled to receive the scaled prediction error vector e′ and
operable to vector quantize the scaled prediction error vector e′
to produce a quantized scaled prediction error vector ê
′ and
a sixth processor coupled to receive the quantized scaled prediction error vector ê
′
for applying a scaling inverse to that applied by said fourth processor to the quantized scaled prediction error vector ê
′
to produce the quantized prediction error vector ê
;
where said second processor determines the prediction vector p in one of an MA predictor or an AR predictor depending on the frame classification information such that if the frame is stationary voiced then the prediction vector p is equal to the output of the AR predictor else the prediction vector p is equal to the output of the MA predictor, where said MA predictor operates on quantized prediction error vectors from previous frames and said AR predictor operates on quantized input LP parameter vectors from previous frames; and
where the quantized input LP parameter vector (mean-removed) is constructed by adding the quantized prediction error vector ê
to the prediction vector p;
{circumflex over (x)}=ê
+p.
2 Assignments
0 Petitions
Accused Products
Abstract
The present invention relates to a method and device for quantizing linear prediction parameters in variable bit-rate sound signal coding, in which an input linear prediction parameter vector is received, a sound signal frame corresponding to the input linear prediction parameter vector is classified, a prediction vector is computed, the computed prediction vector is removed from the input linear prediction parameter vector to produce a prediction error vector, and the prediction error vector is quantized. Computation of the prediction vector comprises selecting one of a plurality of prediction schemes in relation to the classification of the sound signal frame, and processing the prediction error vector through the selected prediction scheme. The present invention further relates to a method and device for dequantizing linear prediction parameters in variable bit-rate sound signal decoding.
-
Citations
58 Claims
-
1. Apparatus comprising a switched predictive vector quantizer having an input for receiving an input Linear Prediction (LP) parameter vector z and a first processor for removing a vector of mean LP parameters μ
- from the input LP parameter vector z to produce a mean-removed LP parameter vector x, a second processor for determining a prediction vector p and a third processor for removing the prediction vector p from the mean-removed LP parameter vector x to produce a prediction error vector e, further comprising a fourth processor responsive to frame classification information such that if a frame corresponding to the input LP parameter vector z is stationary voiced then autoregressive (AR) prediction is used and the error vector e is scaled by a certain factor to obtain a scaled prediction error vector e′
, whereas if the frame is not stationary voiced moving average (MA) prediction is used and the scaling factor is equal to one;
further comprising a fifth processor coupled to receive the scaled prediction error vector e′ and
operable to vector quantize the scaled prediction error vector e′
to produce a quantized scaled prediction error vector ê
′ and
a sixth processor coupled to receive the quantized scaled prediction error vector ê
′
for applying a scaling inverse to that applied by said fourth processor to the quantized scaled prediction error vector ê
′
to produce the quantized prediction error vector ê
;
where said second processor determines the prediction vector p in one of an MA predictor or an AR predictor depending on the frame classification information such that if the frame is stationary voiced then the prediction vector p is equal to the output of the AR predictor else the prediction vector p is equal to the output of the MA predictor, where said MA predictor operates on quantized prediction error vectors from previous frames and said AR predictor operates on quantized input LP parameter vectors from previous frames; and
where the quantized input LP parameter vector (mean-removed) is constructed by adding the quantized prediction error vector ê
to the prediction vector p;
{circumflex over (x)}=ê
+p.
- from the input LP parameter vector z to produce a mean-removed LP parameter vector x, a second processor for determining a prediction vector p and a third processor for removing the prediction vector p from the mean-removed LP parameter vector x to produce a prediction error vector e, further comprising a fourth processor responsive to frame classification information such that if a frame corresponding to the input LP parameter vector z is stationary voiced then autoregressive (AR) prediction is used and the error vector e is scaled by a certain factor to obtain a scaled prediction error vector e′
-
2. A method for quantizing linear prediction parameters in variable bit-rate sound signal coding, comprising:
-
receiving an input linear prediction parameter vector; classifying a sound signal frame corresponding to the input linear prediction parameter vector; computing a prediction vector; removing the computed prediction vector from the input linear prediction parameter vector to produce a prediction error vector; scaling the prediction error vector; quantizing the scaled prediction error vector; wherein; computing a prediction vector comprises selecting one of a plurality of prediction schemes in relation to the classification of the sound signal frame, and computing the prediction vector in accordance with the selected prediction scheme; and scaling the prediction error vector comprises selecting at least one of a plurality of scaling scheme in relation to the selected prediction scheme, and scaling the prediction error vector in accordance with the selected scaling scheme. - View Dependent Claims (3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
-
-
19. A method of dequantizing linear prediction parameters in variable bit-rate sound signal decoding, comprising:
-
receiving at least one quantization index; receiving information about classification of a sound signal frame corresponding to said at least one quantization index; recovering a prediction error vector by applying said at least one index to at least one quantization table; reconstructing a prediction vector; and producing a linear prediction parameter vector in response to the recovered prediction error vector and the reconstructed prediction vector; wherein; reconstructing a prediction vector comprises processing the recovered prediction error vector through one of a plurality of prediction schemes depending on the frame classification information. - View Dependent Claims (20, 21, 22, 23, 24, 25, 26, 27, 28)
-
-
29. A device for quantizing linear prediction parameters in variable bit-rate sound signal coding, comprising:
-
means for receiving an input linear prediction parameter vector; means for classifying a sound signal frame corresponding to the input linear prediction parameter vector; means for computing a prediction vector; means for removing the computed prediction vector from the input linear prediction parameter vector to produce a prediction error vector; means for scaling the prediction error vector; means for quantizing the scaled prediction error vector; wherein; the means for computing a prediction vector comprises means for selecting one of a plurality of prediction schemes in relation to the classification of the sound signal frame, and means for computing the prediction vector in accordance with the selected prediction scheme; and the means for scaling the prediction error vector comprises means for selecting at least one of a plurality of scaling scheme in relation to the selected prediction scheme, and means for scaling the prediction error vector in accordance with the selected scaling scheme.
-
-
30. A device for quantizing linear prediction parameters in variable bit-rate sound signal coding, comprising:
-
an input for receiving an input linear prediction parameter vector; a classifier of a sound signal frame corresponding to the input linear prediction parameter vector; a calculator of a prediction vector; a subtractor for removing the computed prediction vector from the input linear prediction parameter vector to produce a prediction error vector; a scaling unit supplied with the prediction error vector, said unit scaling the prediction error vector; and a quantizer of the scaled prediction error vector; wherein; the prediction vector calculator comprises a selector of one of a plurality of prediction schemes in relation to the classification of the sound signal frame, to calculate the prediction vector in accordance with the selected prediction scheme; and the scaling unit comprises a selector of at least one of a plurality of scaling schemes in relation to the selected prediction scheme, to scale the prediction error vector in accordance with the selected scaling scheme. - View Dependent Claims (31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46)
-
-
47. A device for dequantizing linear prediction parameters in variable bit-rate sound signal decoding, comprising:
-
means for receiving at least one quantization index; means for receiving information about classification of a sound signal frame corresponding to said at least one quantization index; means for recovering a prediction error vector by applying said at least one index to at least one quantization table; means for reconstructing a prediction vector; means for producing a linear prediction parameter vector in response to the recovered prediction error vector and the reconstructed prediction vector; wherein; the prediction vector reconstructing means comprises means for processing the recovered prediction error vector through on of a plurality of prediction schemes depending on the frame classification information.
-
-
48. A device for dequantizing linear prediction parameters in variable bit-rate sound signal decoding, comprising:
-
means for receiving at least one quantization index; means for receiving information about classification of a sound signal frame corresponding to said at least one quantization index; at least one quantization table supplied with said at least one quantization index for recovering a prediction error vector; a prediction vector reconstructing unit; a generator of a linear prediction parameter vector in response to the recovered prediction error vector and the reconstructed prediction vector; wherein; the prediction vector reconstructing unit comprises at least one predictor supplied with recovered prediction error vector for processing the recovered prediction error vector through one of a plurality of prediction schemes depending on the frame classification information. - View Dependent Claims (49, 50, 51, 52, 53, 54, 55, 56, 57, 58)
-
Specification