US5533052A
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Adaptive predictive coding with transform domain quantization based on block size adaptation, backward adaptive power gain control, split bit-allocation and zero input response compensation
Assignee: VIZADA Inc
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Filing: 1993-10-15
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Granted: 1996-07-02
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Expires: 2013-10-15
Abstract
Abstract A codec uses a number of different signal processing techniques to improve audio compression. These techniques include (1) dynamically varying the size of the processing block to match the duration of the signal over which the audio signal can be considered to be substantially constant, (2) reducing the power gain of the LPC coefficients to reduce leakage of coding noise from one block into the following block, (3) allocating bits to the residual signal in accordance with both objective and subjective criteria, and (4) computing a modified residual signal to take into account the zero input response of the synthesis filters to the reconstruction noise of past blocks.
Inventors
- 👤 Bangalore R. R. U. Bhaskar
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 13:30
CPC Classifications
G; G10; G10L; G10L19/00; G10L19/02; G10L19/0212; G10L25/00; G10L25/03; G10L25/12
Claims Analysis
Total Claims: 27
Claim 1
Independent Claim
66 words
An adaptive predictive coding method comprising the steps of generating a residual signal by performing short term and long term prediction analysis and filtering on an input signal in accordance with LPC coefficients derived from said input signal, and quantizing said residual signal, said method further comprising the step of reducing the gain of said coefficients and using the reduced gain coefficients for said performing step.
Claim 2
Dependent Claim
66 words
An adaptive predictive coding method comprising the steps of generating a residual signal by performing short term and long term prediction analysis and filtering on an input signal in accordance with LPC coefficients derived from said input signal, and quantizing said residual signal, said method further comprising the step of reducing the gain of said coefficients and using the reduced gain coefficients for said performing step.
Claim 3
Dependent Claim
49 words
An adaptive predictive coding method comprising the steps of generating a residual signal by processing an input signal, and quantizing said residual signal in accordance with a number of allocated bits, said method further comprising the step of allocating quantization bits in accordance with both objective and perceptual criteria.
Claim 4
Dependent Claim
49 words
An adaptive predictive coding method comprising the steps of generating a residual signal by processing an input signal, and quantizing said residual signal in accordance with a number of allocated bits, said method further comprising the step of allocating quantization bits in accordance with both objective and perceptual criteria.
Claim 5
Dependent Claim
54 words
An adaptive predictive coding method comprising the steps of generating a residual signal by processing an input signal, and quantizing said residual signal in accordance with a number of allocated bits, said method further comprising the step of compensating said residual signal prior to quantization in accordance with a synthesis filter zero input response.
Claim 6
Dependent Claim
54 words
An adaptive predictive coding method comprising the steps of generating a residual signal by processing an input signal, and quantizing said residual signal in accordance with a number of allocated bits, said method further comprising the step of compensating said residual signal prior to quantization in accordance with a synthesis filter zero input response.
Claim 7
Dependent Claim
75 words
An adaptive predictive coding method comprising the steps of generating a residual signal by processing an input signal in blocks, and quantizing said residual signal, said method further comprising the step of varying the size of said blocks during processing of said signal, wherein said residual signal is quantized in accordance with a number of allocated bits, said method further comprising the step of allocating quantization bits in accordance with both objective and perceptual criteria.
Claim 8
Dependent Claim
75 words
An adaptive predictive coding method comprising the steps of generating a residual signal by processing an input signal in blocks, and quantizing said residual signal, said method further comprising the step of varying the size of said blocks during processing of said signal, wherein said residual signal is quantized in accordance with a number of allocated bits, said method further comprising the step of allocating quantization bits in accordance with both objective and perceptual criteria.
Claim 9
Dependent Claim
80 words
An adaptive predictive coding method comprising the steps of generating a residual signal by processing an input signal in blocks, and quantizing said residual signal, said method further comprising the step of varying the size of said blocks during processing of said signal, wherein said residual signal is quantized in accordance with a number of allocated bits, said method further comprising the step of compensating said residual signal prior to quantization in accordance with a synthesis filter zero input response.
Claim 10
Dependent Claim
80 words
An adaptive predictive coding method comprising the steps of generating a residual signal by processing an input signal in blocks, and quantizing said residual signal, said method further comprising the step of varying the size of said blocks during processing of said signal, wherein said residual signal is quantized in accordance with a number of allocated bits, said method further comprising the step of compensating said residual signal prior to quantization in accordance with a synthesis filter zero input response.
Claim 11
Dependent Claim
96 words
An adaptive predictive coding method comprising the steps of generating a residual signal by processing an input signal in blocks, and quantizing said residual signal, said method further comprising the step of varying the size of said blocks during processing of said signal, wherein said step of varying said block size comprises using larger block size during periods of said input signal when at least one characteristic of said input signal exhibits relatively little change, and using smaller block size during periods of said input signal when said at least one parameter exhibits relatively greater change.
Claim 12
Dependent Claim
96 words
An adaptive predictive coding method comprising the steps of generating a residual signal by processing an input signal in blocks, and quantizing said residual signal, said method further comprising the step of varying the size of said blocks during processing of said signal, wherein said step of varying said block size comprises using larger block size during periods of said input signal when at least one characteristic of said input signal exhibits relatively little change, and using smaller block size during periods of said input signal when said at least one parameter exhibits relatively greater change.
Claim 13
Dependent Claim
84 words
A coding method according to claim 6, wherein said step of varying said block size comprises the steps of determining the amount of change of said at least one parameter in each new fixed-size sub-block relative to the existing block, and adding the new sub-blocks to said existing block until a sub-block is found to have an amount of change of said one parameter which exceeds a threshold, or until a maximum block size is reached, at which point a new block is begun.
Claim 14
Dependent Claim
15 words
A coding method according to claim 7, wherein said parameter is a spectral distortion measure.
Claim 15
Dependent Claim
38 words
A coding method according to claim 1, wherein said generating step is performed by processing said input signal in blocks, said method further comprising the step of varying the size of said blocks during processing of said signal.
Claim 16
Dependent Claim
39 words
A coding method according to claim 9, wherein said residual signal is quantized in accordance with a number of allocated bits, said method further comprising the step of allocating quantization bits in accordance with both objective and perceptual criteria.
Claim 17
Dependent Claim
44 words
A coding method according to claim 1, wherein said residual signal is quantized in accordance with a number of allocated bits, said method further comprising the step of compensating said residual signal prior to quantization in accordance with a synthesis filter zero input response.
Claim 18
Dependent Claim
77 words
A coding method according to claim 1, wherein said residual signal is quantized in accordance with a number of allocated bits, wherein a first set of LPC coefficients is derived from said input signal, a second set of reduced gain coefficients is derived from said first set of coefficients, with said second set of coefficients being used for said performing step, and wherein said first set of coefficients is used in determining said number of allocated bits.
Claim 19
Dependent Claim
38 words
A coding method according to claim 2, wherein said generating step is performed by processing said input signal in blocks, said method further comprising the step of varying the size of said blocks during processing of said signal.
Claim 20
Dependent Claim
61 words
A coding method according to claim 2, wherein said residual signal is generated by performing short term and long term prediction analysis and filtering on said input signal in accordance with LPC coefficients derived from said input signal, said method further comprising the step of reducing the gain of said coefficients and using the reduced gain coefficients for said performing step.
Claim 21
Dependent Claim
44 words
A coding method according to claim 2, wherein said residual signal is quantized in accordance with a number of allocated bits, said method further comprising the step of compensating said residual signal prior to quantization in accordance with a synthesis filter zero input response.
Claim 22
Dependent Claim
13 words
A method according to claim 2, wherein said objective criteria comprises reconstruction noise.
Claim 23
Dependent Claim
44 words
A method according to claim 2, wherein said subjective criteria comprises a ratio of a power spectrum of a particular band of said input signal to a power spectrum of reconstruction noise occurring when said residual signal is reconstructed from the quantized residual signal.
Claim 24
Dependent Claim
38 words
A coding method according to claim 3, wherein said generating step is performed by processing said input signal in blocks, said method further comprising the step of varying the size of said blocks during processing of said signal.
Claim 25
Dependent Claim
61 words
A coding method according to claim 3, wherein said residual signal is generated by performing short term and long term prediction analysis and filtering on said input signal in accordance with LPC coefficients derived from said input signal, said method further comprising the step of reducing the gain of said coefficients and using the reduced gain coefficients for said performing step.
Claim 26
Dependent Claim
39 words
A coding method according to claim 3, wherein said residual signal is quantized in accordance with a number of allocated bits, said method further comprising the step of allocating quantization bits in accordance with both objective and perceptual criteria.
Claim 27
Dependent Claim
21 words
A method as recited in claim 1, wherein said step of quantizing said residual signal is performed in a frequency domain.
References Cited (Backward Citations)
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