Method for improving the coding efficiency of an audio signal
First Claim
1. A method of coding an audio signal comprising:
- selecting a reference sequence from a number of stored sequences that has the smallest error relative to a sequence of the audio signal to be coded;
calculating pitch predictor coefficients for the selected reference sequence using one of a set of pitch predictor orders;
producing a predicted sequence from the selected reference sequence using the calculated pitch predictor coefficients;
calculating a coding error by comparing the predicted sequence to the sequence to be coded;
calculating pitch predictor coefficients for the selected reference sequence, producing a predicted sequence from the selected reference sequence, and calculating a coding error by comparing the predicted sequence to the sequence to be coded, for each of the remaining orders of the set of pitch predictor orders; and
using an order from the set of pitch predictor orders that results in the smallest coding error to select a coding method for the sequence to be coded.
7 Assignments
0 Petitions
Accused Products
Abstract
Coding an audio signal includes selecting a reference sequence that has the smallest error relative to a sequence of the audio signal, calculating pitch predictor coefficients for the selected reference sequence using one of a set of pitch predictor orders, producing a predicted sequence from the selected reference sequence using the calculated pitch predictor coefficients, and calculating a coding error by comparing the predicted sequence to the sequence to be coded. Coding also includes calculating pitch predictor coefficients for the selected reference sequence, producing a predicted sequence from the selected reference sequence, and calculating a coding error by comparing the predicted sequence to the sequence to be coded, for each of the remaining orders of the set of pitch predictor orders, and using an order from the set of pitch predictor orders that results in the smallest coding error to select a coding method for the sequence to be coded.
98 Citations
45 Claims
-
1. A method of coding an audio signal comprising:
-
selecting a reference sequence from a number of stored sequences that has the smallest error relative to a sequence of the audio signal to be coded;
calculating pitch predictor coefficients for the selected reference sequence using one of a set of pitch predictor orders;
producing a predicted sequence from the selected reference sequence using the calculated pitch predictor coefficients;
calculating a coding error by comparing the predicted sequence to the sequence to be coded;
calculating pitch predictor coefficients for the selected reference sequence, producing a predicted sequence from the selected reference sequence, and calculating a coding error by comparing the predicted sequence to the sequence to be coded, for each of the remaining orders of the set of pitch predictor orders; and
using an order from the set of pitch predictor orders that results in the smallest coding error to select a coding method for the sequence to be coded. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
-
-
15. A method of decoding an audio signal comprising:
-
receiving a coded sequence;
determining if the coded sequence was formed from an original audio signal;
if the coded sequence was not formed from an original audio signal, extracting a pitch predictor order, pitch predictor coefficients, and lag information used to code the coded sequence from the coded sequence;
selecting a reference sequence from a number of stored sequences that has the smallest error relative to the coded sequence based on the lag information;
producing a predicted signal from the selected reference sequence, the extracted pitch predictor order and pitch predictor coefficients; and
transforming the predicted signal, wherein the transformed predicted signal substantially corresponds to the original audio signal;
the method further comprising;
transforming the coded sequence to the original signal if the coded sequence was formed from the original audio signal. - View Dependent Claims (16, 17, 18)
-
-
19. An encoder of a data transmission system for encoding an audio signal, the encoder operable to:
-
select a reference sequence from a number of stored sequences that has the smallest error relative to a sequence of the audio signal to be coded;
calculate pitch predictor coefficients for the selected reference sequence using one of a set of pitch predictor orders;
produce a predicted sequence from the selected reference sequence using the calculated pitch predictor coefficients;
calculate a coding error by comparing the predicted sequence to the sequence to be coded;
calculate pitch predictor coefficients for the selected reference sequence, produce a predicted sequence from the selected reference sequence, and calculate a coding error by comparing the predicted sequence to the sequence to be coded, for each of the remaining orders of the set of pitch predictor orders; and
use an order from the set of pitch predictor orders that results in the smallest coding error to select a coding method for the sequence to be coded. - View Dependent Claims (20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32)
-
-
33. A decoder of a data transmission system for decoding an audio signal, the decoder operable to:
-
receive a coded sequence;
determine if the coded sequence was formed from an original audio signal;
if the coded sequence was not formed from an original audio signal, extract a pitch predictor order, pitch predictor coefficients, and lag information used to code the coded sequence from the coded sequence;
select a reference sequence from a number of stored sequences that has the smallest error relative to the coded sequence based on the lag information;
produce a predicted signal from the selected reference sequence, the extracted pitch predictor order and pitch predictor coefficients; and
transform the predicted signal, wherein the transformed predicted signal substantially corresponds to the original audio signal;
the decoder further operable to;
transform the coded sequence to the original signal if the coded sequence was formed from the original audio signal. - View Dependent Claims (34, 35, 36)
-
-
37. A computer program product for encoding an audio signal comprising a computer useable medium including a computer readable program, wherein the computer readable program when executed on a computer causes the computer to:
-
select a reference sequence from a number of stored sequences that has the smallest error relative to a sequence of the audio signal to be coded;
calculate pitch predictor coefficients for the selected reference sequence using one of a set of pitch predictor orders;
produce a predicted sequence from the selected reference sequence using the calculated pitch predictor coefficients;
calculate a coding error by comparing the predicted sequence to the sequence to be coded;
calculate pitch predictor coefficients for the selected reference sequence, produce a predicted sequence from the selected reference sequence, and calculate a coding error by comparing the predicted sequence to the sequence to be coded, for each of the remaining orders of the set of pitch predictor orders; and
use an order from the set of pitch predictor orders that results in the smallest coding error to select a coding method for the sequence to be coded.
-
-
38. A computer program product for decoding an audio signal comprising a computer useable medium including a computer readable program, wherein the computer readable program when executed on a computer causes the computer to:
-
receive a coded sequence;
determine if the coded sequence was formed from an original audio signal;
if the coded sequence was not formed from an original audio signal, extract a pitch predictor order, pitch predictor coefficients, and lag information used to code the coded sequence from the coded sequence;
select a reference sequence from a number of stored sequences that has the smallest error relative to the coded sequence based on the lag information;
produce a predicted signal from the selected reference sequence, the extracted pitch predictor order and pitch predictor coefficients; and
transform the predicted signal, wherein the transformed predicted signal substantially corresponds to the original audio signal;
wherein the computer readable program when executed on a computer further causes the computer to;
transform the coded sequence to the original signal if the coded sequence was formed from the original audio signal.
-
-
39. An encoder for coding an audio signal comprising:
-
a lag block for selecting a reference sequence from a number of stored sequences that has the smallest error relative to a sequence to be coded;
a coefficient calculator for calculating pitch predictor coefficients for the selected reference sequence using one of a set of pitch predictor orders;
a pitch predictor block for producing a predicted sequence from the selected reference sequence using the calculated pitch predictor coefficients;
a calculation block for calculating a coding error by comparing the predicted sequence to the sequence to be coded;
wherein the coefficient calculator, the pitch predictor block, and the calculation block are operable to calculate pitch predictor coefficients for the selected reference sequence, produce a predicted sequence from the selected reference sequence, and calculate a coding error by comparing the predicted sequence to the sequence to be coded, for each of the remaining orders of the set of pitch predictor orders; and
wherein the calculation block is further operable to use an order from the set of pitch predictor orders that results in the smallest coding error to select a coding method for the sequence to be coded.
-
-
40. A decoder for decoding an audio signal comprising:
-
a receiving device for receiving a coded sequence;
a decoder for determining if the coded sequence was formed from an original audio signal;
the receiving device operable to extract a pitch predictor order, pitch predictor coefficients, and lag information used to code the coded sequence from the coded sequence if the coded sequence was not formed from an original audio signal;
a pitch predictor block for selecting a reference sequence from a number of stored sequences that has the smallest error relative to the coded sequence based on the lag information;
the pitch predictor block operable to produce a predicted signal from the selected reference sequence, the extracted pitch predictor order and pitch predictor coefficients, and to transform the predicted signal, wherein the transformed predicted signal substantially corresponds to the original audio signal;
wherein the decoder is operable to transform the coded sequence to the original signal if the coded sequence was formed from the original audio signal
-
-
41. A data transmission system for coding an audio signal comprising:
circuitry for coding having;
a lag block for selecting a reference sequence from a number of stored sequences that has the smallest error relative to a sequence to be coded;
a coefficient calculator for calculating pitch predictor coefficients for the selected reference sequence using one of a set of pitch predictor orders;
a pitch predictor block for producing a predicted sequence from the selected reference sequence using the calculated pitch predictor coefficients;
a calculation block for calculating a coding error by comparing the predicted sequence to the sequence to be coded;
wherein the coefficient calculator, the pitch predictor block, and the calculation block are operable to calculate pitch predictor coefficients for the selected reference sequence, produce a predicted sequence from the selected reference sequence, and calculate a coding error by comparing the predicted sequence to the sequence to be coded, for each of the remaining orders of the set of pitch predictor orders; and
wherein the calculation block is further operable to use an order from the set of pitch predictor orders that results in the smallest coding error to select a coding method for the sequence to be coded.
-
42. A data transmission system for decoding an audio signal comprising:
circuitry for decoding having;
a receiving device for receiving a coded sequence;
a decoder for determining if the coded sequence was formed from an original audio signal;
the receiving device operable to extract a pitch predictor order, pitch predictor coefficients, and lag information used to code the coded sequence from the coded sequence if the coded sequence was not formed from an original audio signal;
a pitch predictor block for selecting a reference sequence from a number of stored sequences that has the smallest error relative to the coded sequence based on the lag information;
the pitch predictor block operable to produce a predicted signal from the selected reference sequence, the extracted pitch predictor order and pitch predictor coefficients, and to transform the predicted signal, wherein the transformed predicted signal substantially corresponds to the original audio signal;
wherein the decoder is operable to transform the coded sequence to the original signal if the coded sequence was formed from the original audio signal
-
43. A data transmission system comprising:
-
circuitry for coding having;
a lag block for selecting a reference sequence from a number of stored sequences that has the smallest error relative to a sequence of an original audio signal to be coded;
a coefficient calculator for calculating pitch predictor coefficients for the selected reference sequence using one of a set of pitch predictor orders;
a pitch predictor block for producing a predicted sequence from the selected reference sequence using the calculated pitch predictor coefficients;
a calculation block for calculating a coding error by comparing the predicted sequence to the sequence to be coded;
wherein the coefficient calculator, the pitch predictor block, and the calculation block are operable to calculate pitch predictor coefficients for the selected reference sequence, produce a predicted sequence from the selected reference sequence, and calculate a coding error by comparing the predicted sequence to the sequence to be coded, for each of the remaining orders of the set of pitch predictor orders; and
wherein the calculation block is further operable to use an order from the set of pitch predictor orders that results in the smallest coding error to select a coding method for the sequence to be coded and to generate a coded sequence;
the data transmission system also including circuitry for decoding having;
a receiving device for receiving the coded sequence;
a decoder for determining if the coded sequence was formed from the original audio signal;
the receiving device operable to extract a pitch predictor order, pitch predictor coefficients, and lag information used to code the coded sequence from the coded sequence if the coded sequence was not formed from the original audio signal;
a pitch predictor block for selecting a reference sequence from a number of stored sequences that has the smallest error relative to the coded sequence based on the lag information;
the pitch predictor block operable to produce a predicted signal from the selected reference sequence, the extracted pitch predictor order and pitch predictor coefficients, and to transform the predicted signal, wherein the transformed predicted signal substantially corresponds to the original audio signal;
wherein the decoder is operable to transform the coded sequence to the original signal if the coded sequence was formed from the original audio signal.
-
-
44. A data structure for transmitting a coded sequence comprising:
an indication that the coded sequence was not formed from an original audio signal, a pitch predictor order, pitch predictor coefficients, and lag information determined by;
selecting a reference sequence from a number of stored sequences that has the smallest lag relative to a sequence of the original audio signal;
calculating pitch predictor coefficients for the selected reference sequence using one of a set of pitch predictor orders;
producing a predicted sequence from the selected reference sequence using the calculated pitch predictor coefficients;
calculating a coding error by comparing the predicted sequence to the sequence to be coded;
calculating pitch predictor coefficients for the selected reference sequence, producing a predicted sequence from the selected reference sequence, and calculating a coding error by comparing the predicted sequence to the sequence to be coded, for each of the remaining orders of the set of pitch predictor orders; and
including the lag information and the pitch predictor order and pitch predictor coefficients in the data structure that result in the smallest coding error.
-
45. A data structure for transmitting a coded sequence comprising:
-
an indication that the coded sequence was formed from the original audio signal; and
frequency spectrum values of the original audio signal.
-
Specification