Generalized analysis-by-synthesis speech coding method and apparatus
First Claim
1. A method for coding an original signal representative of speech, the method comprising the steps of:
- a. generating a plurality of distinct trial original signals by varying the original signal a corresponding plurality of times, each of said distinct trial original signals corresponding to and being a different variation of the original signal;
b. for each of the plurality of distinct trial original signals, performing an encoding of said trial original signal to generate a corresponding encoded trial original signal, performing a decoding of said corresponding encoded trial original signal to generate a corresponding synthesized trial original signal, and comparing said trial original signal to said corresponding synthesized trial original signal to determine a corresponding measure of similarity therebetween;
c. selecting one of said trial original signals for use in coding the original signal based on an evaluation of one or more of said measures of similarity; and
d. coding the original signal based on the encoded trial original signal corresponding to the selected trial original signal.
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Abstract
A generalized analysis-by-synthesis method and apparatus are disclosed. A plurality of trial original signals are generated based on an original signal for coding. The trial original signals are constrained to be perceptually similar to the original signal. Trial original signals are coded to produce one or more parameters representative thereof. Estimates of the trial original signals are synthesized from these parameters. Errors between the trial original signals and the synthesized estimates are determined. A coded representation of the original signal is determined which comprises parameters of the trial original signal having an associated error which satisfies an error evaluation process. Trial original signals may be generated by application of time-warps or time-shifts to the original signal. Coding of a trial original signal may be performed with conventional analysis-by-synthesis coding such as code-excited linear prediction coding (CELP). A minimum square error process may serve as the error criterion.
36 Citations
20 Claims
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1. A method for coding an original signal representative of speech, the method comprising the steps of:
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a. generating a plurality of distinct trial original signals by varying the original signal a corresponding plurality of times, each of said distinct trial original signals corresponding to and being a different variation of the original signal;
b. for each of the plurality of distinct trial original signals, performing an encoding of said trial original signal to generate a corresponding encoded trial original signal, performing a decoding of said corresponding encoded trial original signal to generate a corresponding synthesized trial original signal, and comparing said trial original signal to said corresponding synthesized trial original signal to determine a corresponding measure of similarity therebetween;
c. selecting one of said trial original signals for use in coding the original signal based on an evaluation of one or more of said measures of similarity; and
d. coding the original signal based on the encoded trial original signal corresponding to the selected trial original signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
wherein the decoding of said encoded trial original signal comprises the step of generating said corresponding synthesized trial original signal based on one or more of said parameters. -
9. The method of claim 1 wherein each of the synthesized trial original signals is of a duration equal to a subframe.
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10. The method of claim 1 wherein each trial original signal is of a duration equal to a subframe.
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11. An apparatus for coding an original signal representative of speech, the apparatus comprising:
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a. means for generating a plurality of distinct trial original signals by varying the original signal a corresponding plurality of times, each of said distinct trial original signals corresponding to and being a different variation of the original signal;
b. means, applied to each of the plurality of distinct trial original signals, for performing an encoding of said trial original signal to generate a corresponding encoded trial original signal, for performing a decoding of said corresponding encoded trial original signal to generate a corresponding synthesized trial original signal, and for comparing said trial original signal to said corresponding synthesized trial original signal to determine a corresponding measure of similarity therebetween;
c. means for selecting one of said trial original signals for use in coding the original signal based on an evaluation of one or more of said measures of similarity; and
d. means for coding the original signal based on the encoded trial original signal corresponding to the selected trial original signal. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20)
wherein said means for performing an encoding of said trial original signals comprises means for producing one or more parameters representative thereof, and wherein said means for performing a decoding of said encoded trial original signals comprises means for generating said corresponding synthesized trial original signal based on one or more of said parameters. -
19. The apparatus of claim 11 wherein each of the synthesized trial original signals is of a duration equal to a subframe.
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20. The apparatus of claim 11 wherein each trial original signal is of a duration equal to a subframe.
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Specification