Voice encoding device, voice decoding device, and methods therefor
View Patent ↗An encoding device capable of realizing a scalable CODEC of a high performance. In this encoding device, an LPC analyzing unit ( 551 ) analyzes an input voice ( 301 ) efficiently with a synthesized LPC parameter obtained from a core decoder ( 305 ), to acquire an encoded LPC coefficient. An adaptive code note ( 552 ) is stored with its sound source codes, as acquired from the core decoder ( 305 ). The adaptive code note ( 552 ) and a stochastic code note ( 553 ) send sound source samples to a gain adjusting unit ( 554 ). This gain adjusting unit ( 554 ) multiplies the individual sound source samples by an amplification based on the gain parameters acquired from the core decoder ( 305 ), and then adds the products to acquire sound source vectors. These vectors are sent to an LPC synthesizing unit ( 555 ). This LPC synthesizing unit ( 555 ) filters the sound source vectors acquired at the gain adjusting unit ( 554 ), with the LPC parameter, to acquire a synthetic signal.
1. A speech encoding apparatus that encodes an input signal using encoded information of n layers, n being an integer greater than or equal to 2, the speech encoding apparatus comprising:
a base layer encoder that encodes the input signal to generate the encoded information of layer 1;
a decoder of layer i that decodes the encoded information of layer i , i being an integer greater than 1 and less than or equal to n−1, to generate a decoded signal of layer i;
an adder, comprising a processor, that adds either a difference signal of layer 1 which is a difference between the input signal and the decoded signal of layer 1 or a difference signal of layer i which is a difference between the decoded signal of layer i−1 and the decoded signal of layer i; and
an enhancement layer encoder of layer i+1 that encodes the difference signal of layer i to generate encoded information of layer i+1;
wherein the enhancement layer encoder of layer i+1 performs an encoding process utilizing decoding parameters received separately from the difference signal and from a decoding section of layer j, j being an integer less than or equal to i and obtained in the decoding process of the decoding section of layer j.
2. A speech encoding apparatus according to claim 1 wherein the enhancement layer encoder of layer i+1 is a CELP type encoder that utilizes LPC parameter information obtained through decoding in the decoding section of layer j.
3. A speech encoding apparatus according to claim 1 wherein the enhancement layer encoder of layer i+1 is a CELP type encoder that utilizes information of an adaptive codebook obtained through decoding in the decoder of layer j.
4. A speech encoding apparatus according to claim 1 wherein the enhancement layer encoder of layer i+1 is a CELP type encoder that utilizes gain information obtained through decoding in the decoder of layer j.
5. A speech decoding apparatus that decodes encoded information of n layers, n being an integer greater than or equal to 2, the speech decoding apparatus comprising:
a base layer decoder that decodes the inputted encoded information of layer 1;
a decoder of layer i that decodes the encoded information of layer i+1, i being an integer greater than 1 and less than or equal to n+1, to generate a decoded signal of layer i+1; and
an adder, comprising a processor, that adds the decoded signal of each layer,
wherein the decoder of layer i+1 performs a decoding process utilizing decoding parameters received separately from the encoded information of layer i+1 and from a decoder of layer j, j being an integer less than or equal to i and obtained in a decoding process of the decoder of layer j.
6. A speech decoding apparatus according to claim 5 wherein the decoder of layer i+1 is a CELP type decoder that utilizes LPC parameter information obtained through decoding in the decoder of layer j.
7. A speech decoding apparatus according to claim 5 wherein the decoder of layer i+1 is a CELP type decoder that utilizes information of an adaptive codebook obtained through decoding in the decoder of layer j.
8. A speech decoding apparatus according to claim 5 wherein the decoder of layer i+1 is a CELP type decoder that utilizes gain information obtained through decoding in the decoder of layer j.
9. A speech encoding method that encodes input signals using the encoded information of n layers, n being an integer greater than or equal to 2, the speech encoding method comprising:
a base layer encoding process that encodes the input signal to generate the encoded information of layer 1,
a decoding process of layer i that decodes the encoded information of layer i, i being an integer greater than 1 and less than or equal to n−1 to generate the decoded signal of layer i;
an addition process that either determines a difference signal of layer 1 which is a difference between the input signal and the decoded signal of layer 1 or a difference signal of layer i which is a difference between the decoded signal of layer i−1 and the decoded signal of layer i; and
an enhancement layer encoding process of layer i+1 that encodes the difference signal of layer i to generate encoded information of layer i+1;
wherein the enhancement layer encoding process of layer i+1 an encoding process utilizing decoding parameters received separately from the difference signal and from a decoding process of layer j, j being an integer less than or equal to i and obtained in the decoding process of layer j.
10. A speech decoding method that decodes encoded information of n layers, n being an integer greater than or equal to 2, the speech decoding method comprising:
a base layer decoding process that decodes the inputted encoded information of layer 1;
a decoding process of decoding encoded information of layer i+1, i being an integer greater than 1 and less than or equal to n−1 to generate a decoded signal of layer i+1; and
an addition process that adds the decoded signal of each layer;
wherein the decoding process of layer i+1 performs a decoding process utilizing decoding parameters received separately from the encoded information of layer i+1 and from a decoding process of layer j, j being an integer less than or equal to i and obtained in the decoding process of layer j.