CA2489441A1 - Audio coding system using spectral hole filling - Google Patents
Audio coding system using spectral hole filling Download PDFInfo
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- CA2489441A1 CA2489441A1 CA002489441A CA2489441A CA2489441A1 CA 2489441 A1 CA2489441 A1 CA 2489441A1 CA 002489441 A CA002489441 A CA 002489441A CA 2489441 A CA2489441 A CA 2489441A CA 2489441 A1 CA2489441 A1 CA 2489441A1
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- 230000003595 spectral effect Effects 0.000 title claims abstract 109
- 238000000034 method Methods 0.000 claims abstract 35
- 230000005236 sound signal Effects 0.000 claims abstract 23
- 230000015572 biosynthetic process Effects 0.000 claims 18
- 238000003786 synthesis reaction Methods 0.000 claims 18
- 230000000873 masking effect Effects 0.000 claims 12
- 230000002123 temporal effect Effects 0.000 claims 6
- 230000015556 catabolic process Effects 0.000 abstract 1
- 238000006731 degradation reaction Methods 0.000 abstract 1
- 238000013139 quantization Methods 0.000 abstract 1
Classifications
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- G—PHYSICS
- G10—MUSICAL INSTRUMENTS; ACOUSTICS
- G10L—SPEECH ANALYSIS OR SYNTHESIS; SPEECH RECOGNITION; SPEECH OR VOICE PROCESSING; SPEECH OR AUDIO CODING OR DECODING
- G10L19/00—Speech or audio signals analysis-synthesis techniques for redundancy reduction, e.g. in vocoders; Coding or decoding of speech or audio signals, using source filter models or psychoacoustic analysis
- G10L19/02—Speech or audio signals analysis-synthesis techniques for redundancy reduction, e.g. in vocoders; Coding or decoding of speech or audio signals, using source filter models or psychoacoustic analysis using spectral analysis, e.g. transform vocoders or subband vocoders
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- G—PHYSICS
- G10—MUSICAL INSTRUMENTS; ACOUSTICS
- G10L—SPEECH ANALYSIS OR SYNTHESIS; SPEECH RECOGNITION; SPEECH OR VOICE PROCESSING; SPEECH OR AUDIO CODING OR DECODING
- G10L19/00—Speech or audio signals analysis-synthesis techniques for redundancy reduction, e.g. in vocoders; Coding or decoding of speech or audio signals, using source filter models or psychoacoustic analysis
- G10L19/02—Speech or audio signals analysis-synthesis techniques for redundancy reduction, e.g. in vocoders; Coding or decoding of speech or audio signals, using source filter models or psychoacoustic analysis using spectral analysis, e.g. transform vocoders or subband vocoders
- G10L19/032—Quantisation or dequantisation of spectral components
- G10L19/035—Scalar quantisation
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- G—PHYSICS
- G10—MUSICAL INSTRUMENTS; ACOUSTICS
- G10L—SPEECH ANALYSIS OR SYNTHESIS; SPEECH RECOGNITION; SPEECH OR VOICE PROCESSING; SPEECH OR AUDIO CODING OR DECODING
- G10L21/00—Processing of the speech or voice signal to produce another audible or non-audible signal, e.g. visual or tactile, in order to modify its quality or its intelligibility
- G10L21/02—Speech enhancement, e.g. noise reduction or echo cancellation
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- G—PHYSICS
- G10—MUSICAL INSTRUMENTS; ACOUSTICS
- G10L—SPEECH ANALYSIS OR SYNTHESIS; SPEECH RECOGNITION; SPEECH OR VOICE PROCESSING; SPEECH OR AUDIO CODING OR DECODING
- G10L21/00—Processing of the speech or voice signal to produce another audible or non-audible signal, e.g. visual or tactile, in order to modify its quality or its intelligibility
- G10L21/02—Speech enhancement, e.g. noise reduction or echo cancellation
- G10L21/038—Speech enhancement, e.g. noise reduction or echo cancellation using band spreading techniques
Abstract
Audio coding processes like quantization can cause spectral components of an encoded audio signal to be set to zero, creating spectral holes in the signal.
These spectral holes can degrade the perceived quality of audio signals that are reproduced by audio coding systems. An improved decoder avoids or reduces the degradation by filling the spectral holes with synthesized spectral components. An improved encoder may also be used to realize further improvements in the decoder.
These spectral holes can degrade the perceived quality of audio signals that are reproduced by audio coding systems. An improved decoder avoids or reduces the degradation by filling the spectral holes with synthesized spectral components. An improved encoder may also be used to realize further improvements in the decoder.
Claims (45)
1. A method for generating audio information, wherein the method comprises:
receiving an input signal and obtaining therefrom a set of subband signals each having one or more spectral components representing spectral content of an audio signal;
identifying within the set of subband signals a particular subband signal in which one or more spectral components have a non-zero value and are quantized by a quantizer having a minimum quantizing level that corresponds to a threshold, and in which a plurality of spectral components have a zero value;
generating synthesized spectral components that correspond to respective zero-valued spectral components in the particular subband signal and that are scaled according to a scaling envelope less than or equal to the threshold;
generating a modified set of subband signals by substituting the synthesized spectral components for corresponding zero-valued spectral components in the particular subband signal; and generating the audio information by applying a synthesis filterbank to the modified set of subband signals.
receiving an input signal and obtaining therefrom a set of subband signals each having one or more spectral components representing spectral content of an audio signal;
identifying within the set of subband signals a particular subband signal in which one or more spectral components have a non-zero value and are quantized by a quantizer having a minimum quantizing level that corresponds to a threshold, and in which a plurality of spectral components have a zero value;
generating synthesized spectral components that correspond to respective zero-valued spectral components in the particular subband signal and that are scaled according to a scaling envelope less than or equal to the threshold;
generating a modified set of subband signals by substituting the synthesized spectral components for corresponding zero-valued spectral components in the particular subband signal; and generating the audio information by applying a synthesis filterbank to the modified set of subband signals.
2. The method according to claim 1 wherein the scaling envelope is uniform.
3. The method according to claim 1 or 2 wherein the synthesis filterbank is implemented by a block transform that has spectral leakage between adjacent spectral components and the scaling envelope varies at a rate substantially equal to a rate of roll off of the spectral leakage of the block transform.
4. The method according to any one of claims 1 through 3 wherein the synthesis filterbank is implemented by a block transform and the method comprises:
applying a frequency-domain filter to one or more spectral components in the set of subband signals; and deriving the scaling envelope from an output of the frequency-domain filter.
applying a frequency-domain filter to one or more spectral components in the set of subband signals; and deriving the scaling envelope from an output of the frequency-domain filter.
5. The method according to claim 4 that comprises varying the response of the frequency-domain filter as a function of frequency.
6. The method according to any one of claims 1 through 5 that comprises:
obtaining a measure of tonality of the audio signal represented by the set of subband signals; and adapting the scaling envelope in response to the measure of tonality.
obtaining a measure of tonality of the audio signal represented by the set of subband signals; and adapting the scaling envelope in response to the measure of tonality.
7. The method according to claim 6 that obtains the measure of tonality from the input signal.
8. The method according to claim 6 that comprises deriving the measure of tonality from the way in which the zero-valued spectral components are arranged in the particular subband signal.
9. The method according to any one of claims 1 through 8 wherein the synthesis filterbank is implemented by a block transform and the method comprises:
obtaining a sequence of sets of subband signals from the input signal;
identifying a common subband signal in the sequence of sets of subband signals where, for each set in the sequence, one or more spectral components have a non-zero value and a plurality of spectral components have a zero value;
identifying a common spectral component within the common subband signal that has a zero value in a plurality of adjacent sets in the sequence that are either preceded or followed by a set with the common spectral components having a non-zero value;
scaling the synthesized spectral components that correspond to the zero-valued common spectral components according to the scaling envelope that varies from set to set in the sequence according to temporal masking characteristics of the human auditory system;
generating a sequence of modified sets of subband signals by substituting the synthesized spectral components for the corresponding zero-valued common spectral components in the sets; and generating the audio information by applying the synthesis filterbank to the sequence of modified sets of subband signals.
obtaining a sequence of sets of subband signals from the input signal;
identifying a common subband signal in the sequence of sets of subband signals where, for each set in the sequence, one or more spectral components have a non-zero value and a plurality of spectral components have a zero value;
identifying a common spectral component within the common subband signal that has a zero value in a plurality of adjacent sets in the sequence that are either preceded or followed by a set with the common spectral components having a non-zero value;
scaling the synthesized spectral components that correspond to the zero-valued common spectral components according to the scaling envelope that varies from set to set in the sequence according to temporal masking characteristics of the human auditory system;
generating a sequence of modified sets of subband signals by substituting the synthesized spectral components for the corresponding zero-valued common spectral components in the sets; and generating the audio information by applying the synthesis filterbank to the sequence of modified sets of subband signals.
10. The method according to any one of claims 1 through 9 wherein the synthesis filterbank is implemented by a block transform and the method generates the synthesized spectral components by spectral translation of other spectral components in the set of subband signals.
11. The method according to any one of claims 1 through 10 wherein the scaling envelope varies according to temporal masking characteristics of the human auditory system.
12. A method for generating an output signal, wherein the method comprises:
generating a set of subband signals each having one or more spectral components representing spectral content of an audio signal by quantizing information that is obtained by applying an analysis filterbank to audio information;
identifying within the set of subband signals a particular subband signal in which one or more spectral components have a non-zero value and are quantized by a quantizer having a minimum quantizing level that corresponds to a threshold, and in which a plurality of spectral components have a zero value;
deriving scaling control information from the spectral content of the audio signal, wherein the scaling control information controls scaling of synthesized spectral components to be synthesized and substituted for the spectral components having a zero value in a receiver that generates audio information in response to the output signal; and generating the output signal by assembling the scaling control information and information representing the set of subband signals.
generating a set of subband signals each having one or more spectral components representing spectral content of an audio signal by quantizing information that is obtained by applying an analysis filterbank to audio information;
identifying within the set of subband signals a particular subband signal in which one or more spectral components have a non-zero value and are quantized by a quantizer having a minimum quantizing level that corresponds to a threshold, and in which a plurality of spectral components have a zero value;
deriving scaling control information from the spectral content of the audio signal, wherein the scaling control information controls scaling of synthesized spectral components to be synthesized and substituted for the spectral components having a zero value in a receiver that generates audio information in response to the output signal; and generating the output signal by assembling the scaling control information and information representing the set of subband signals.
13. The method according to claim 12 that comprises:
obtaining a measure of tonality of the audio signal represented by the set of subband signals; and deriving the scaling control information from the measure of tonality.
obtaining a measure of tonality of the audio signal represented by the set of subband signals; and deriving the scaling control information from the measure of tonality.
14. The method according to claim 12 or 13 that comprises:
obtaining an estimated psychoacoustic masking threshold of the audio signal represented by the set of subband signals; and deriving the scaling control information from the estimated psychoacoustic masking threshold.
obtaining an estimated psychoacoustic masking threshold of the audio signal represented by the set of subband signals; and deriving the scaling control information from the estimated psychoacoustic masking threshold.
15. The method according to any one of claims 12 through 14 that comprises:
obtaining two measures of spectral levels for portions of the audio signal represented by the non-zero-valued and the zero-valued spectral components; and deriving the scaling control information from the two measures of spectral levels.
obtaining two measures of spectral levels for portions of the audio signal represented by the non-zero-valued and the zero-valued spectral components; and deriving the scaling control information from the two measures of spectral levels.
16. An apparatus for generating audio information, wherein the apparatus comprises:
a deformatter that receives an input signal and obtains therefrom a set of subband signals each having one or more spectral components representing spectral content of an audio signal;
a decoder coupled to the deformatter that identifies within the set of subband signals a particular subband signal in which one or more spectral components have a non-zero value and are quantized by a quantizer having a minimum quantizing level that corresponds to a threshold, and in which a plurality of spectral components have a zero value, that generates synthesized spectral components that correspond to respective zero-valued spectral components in the particular subband signal and are scaled according to a scaling envelope less than or equal to the threshold, and that generates a modified set of subband signals by substituting the synthesized spectral components for corresponding zero-valued spectral components in the particular subband signal; and a synthesis filterbank coupled to the decoder that generates the audio information in response to the modified set of subband signals.
a deformatter that receives an input signal and obtains therefrom a set of subband signals each having one or more spectral components representing spectral content of an audio signal;
a decoder coupled to the deformatter that identifies within the set of subband signals a particular subband signal in which one or more spectral components have a non-zero value and are quantized by a quantizer having a minimum quantizing level that corresponds to a threshold, and in which a plurality of spectral components have a zero value, that generates synthesized spectral components that correspond to respective zero-valued spectral components in the particular subband signal and are scaled according to a scaling envelope less than or equal to the threshold, and that generates a modified set of subband signals by substituting the synthesized spectral components for corresponding zero-valued spectral components in the particular subband signal; and a synthesis filterbank coupled to the decoder that generates the audio information in response to the modified set of subband signals.
17. The apparatus according to claim 16 wherein the scaling envelope is uniform.
18. The apparatus according to claim 16 or 17 wherein the synthesis filterbank is implemented by a block transform that has spectral leakage between adjacent spectral components and the scaling envelope varies at a rate substantially equal to a rate of roll off of the spectral leakage of the block transform.
19. The apparatus according to any one of claims 16 through 18 wherein the synthesis filterbank is implemented by a block transform and the decoder:
applies a frequency-domain filter to one or more spectral components in the set of subband signals; and derives the scaling envelope from an output of the frequency-domain filter.
applies a frequency-domain filter to one or more spectral components in the set of subband signals; and derives the scaling envelope from an output of the frequency-domain filter.
20. The apparatus according to claim 19 wherein the decoder varies the response of the frequency-domain filter as a function of frequency.
21. The apparatus according to any one of claims 16 through 20 wherein the decoder:
obtains a measure of tonality of the audio signal represented by the set of subband signals; and adapts the scaling envelope in response to the measure of tonality.
obtains a measure of tonality of the audio signal represented by the set of subband signals; and adapts the scaling envelope in response to the measure of tonality.
22. The apparatus according to claim 21 that obtains the measure of tonality from the input signal.
23. The apparatus according to claim 21 wherein the decoder derives the measure of tonality from the way in which the zero-valued spectral components are arranged in the particular subband signal.
24. The apparatus according to any one of claims 16 through 23 wherein the synthesis filterbank is implemented by a block transform and:
the deformatter obtains a sequence of sets of subband signals from the input signal;
the decoder identifies a common subband signal in the sequence of sets of subband signals where, for each set in the sequence, one or more spectral components have a non-zero value and a plurality of spectral components have a zero value, identifies a common spectral component within the common subband signal that has a zero value in a plurality of adjacent sets in the sequence that are either preceded or followed by a set with the common spectral components having a non-zero value, scales the synthesized spectral components that correspond to the zero-valued common spectral components according to the scaling envelope that varies from set to set in the sequence according to temporal masking characteristics of the human auditory system;
and generates a sequence of modified sets of subband signals by substituting the synthesized spectral components for the corresponding zero-valued common spectral components in the sets; and the synthesis filterbank generates the audio information in response to the sequence of modified sets of subband signals.
the deformatter obtains a sequence of sets of subband signals from the input signal;
the decoder identifies a common subband signal in the sequence of sets of subband signals where, for each set in the sequence, one or more spectral components have a non-zero value and a plurality of spectral components have a zero value, identifies a common spectral component within the common subband signal that has a zero value in a plurality of adjacent sets in the sequence that are either preceded or followed by a set with the common spectral components having a non-zero value, scales the synthesized spectral components that correspond to the zero-valued common spectral components according to the scaling envelope that varies from set to set in the sequence according to temporal masking characteristics of the human auditory system;
and generates a sequence of modified sets of subband signals by substituting the synthesized spectral components for the corresponding zero-valued common spectral components in the sets; and the synthesis filterbank generates the audio information in response to the sequence of modified sets of subband signals.
25. The apparatus according to any one of claims 16 through 24 wherein the synthesis filterbank is implemented by a block transform and the decoder generates the synthesized spectral components by spectral translation of other spectral components in the set of subband signals.
26. The apparatus according to any one of claims 16 through 25 wherein the scaling envelope varies according to temporal masking characteristics of the human auditory system.
27. An apparatus for generating an output signal, wherein the apparatus comprises:
an analysis filterbank that generates in response to audio information a set of subband signals each having one or more spectral components representing spectral content of an audio signal;
quantizers coupled to the analysis filterbank that quantize the spectral components;
an encoder coupled to the quantizers that identifies within the set of subband signals a particular subband signal in which one or more spectral components have a non-zero value and are quantized by a quantizer having a minimum quantizing level that corresponds to a threshold and in which a plurality of spectral components have a zero value, derives scaling control information from the spectral content of the audio signal, wherein the scaling control information controls scaling of synthesized spectral components to be synthesized and substituted for the spectral components having a zero value in a receiver that generates audio information in response to the output signal;
and a formatter coupled to the encoder that generates the output signal by assembling the scaling control information and information representing the set of subband signals.
an analysis filterbank that generates in response to audio information a set of subband signals each having one or more spectral components representing spectral content of an audio signal;
quantizers coupled to the analysis filterbank that quantize the spectral components;
an encoder coupled to the quantizers that identifies within the set of subband signals a particular subband signal in which one or more spectral components have a non-zero value and are quantized by a quantizer having a minimum quantizing level that corresponds to a threshold and in which a plurality of spectral components have a zero value, derives scaling control information from the spectral content of the audio signal, wherein the scaling control information controls scaling of synthesized spectral components to be synthesized and substituted for the spectral components having a zero value in a receiver that generates audio information in response to the output signal;
and a formatter coupled to the encoder that generates the output signal by assembling the scaling control information and information representing the set of subband signals.
28. The apparatus according to claim 27 that:
obtains a measure of tonality of the audio signal represented by the set of subband signals; and derives the scaling control information from the measure of tonality.
obtains a measure of tonality of the audio signal represented by the set of subband signals; and derives the scaling control information from the measure of tonality.
29. The apparatus according to claim 27 or 28 comprising a modelling component that:
obtains an estimated psychoacoustic masking threshold of the audio signal represented by the set of subband signals; and derives the scaling control information from the estimated psychoacoustic masking threshold.
obtains an estimated psychoacoustic masking threshold of the audio signal represented by the set of subband signals; and derives the scaling control information from the estimated psychoacoustic masking threshold.
30. The apparatus according to any one of claims 27 through 29 that:
obtains two measures of spectral levels for portions of the audio signal represented by the non-zero-valued and the zero-valued spectral components;
and derives the scaling control information from the two measures of spectral levels.
obtains two measures of spectral levels for portions of the audio signal represented by the non-zero-valued and the zero-valued spectral components;
and derives the scaling control information from the two measures of spectral levels.
31. A medium that conveys a program of instructions and is readable by a device for executing the program of instructions to perform a method for generating audio information, wherein the method comprises:
receiving an input signal and obtaining therefrom a set of subband signals each having one or more spectral components representing spectral content of an audio signal;
identifying within the set of subband signals a particular subband signal in which one or more spectral components have a non-zero value and are quantized by a quantizer having a minimum quantizing level that corresponds to a threshold, and in which a plurality of spectral components have a zero value;
generating synthesized spectral components that correspond to respective zero-valued spectral components in the particular subband signal and that are scaled according to a scaling envelope less than or equal to the threshold;
generating a modified set of subband signals by substituting the synthesized spectral components for corresponding zero-valued spectral components in the particular subband signal; and generating the audio information by applying a synthesis filterbank to the modified set of subband signals.
receiving an input signal and obtaining therefrom a set of subband signals each having one or more spectral components representing spectral content of an audio signal;
identifying within the set of subband signals a particular subband signal in which one or more spectral components have a non-zero value and are quantized by a quantizer having a minimum quantizing level that corresponds to a threshold, and in which a plurality of spectral components have a zero value;
generating synthesized spectral components that correspond to respective zero-valued spectral components in the particular subband signal and that are scaled according to a scaling envelope less than or equal to the threshold;
generating a modified set of subband signals by substituting the synthesized spectral components for corresponding zero-valued spectral components in the particular subband signal; and generating the audio information by applying a synthesis filterbank to the modified set of subband signals.
32. The medium according to claim 31 wherein the scaling envelope is uniform.
33. The medium according to claim 31 or 32 wherein the synthesis filterbank is implemented by a block transform that has spectral leakage between adjacent spectral components and the scaling envelope varies at a rate substantially equal to a rate of roll off of the spectral leakage of the block transform.
34. The medium according to any one of claims 31 through 33 wherein the synthesis filterbank is implemented by a block transform and the method comprises:
applying a frequency-domain filter to one or more spectral components in the set of subband signals; and deriving the scaling envelope from an output of the frequency-domain filter.
applying a frequency-domain filter to one or more spectral components in the set of subband signals; and deriving the scaling envelope from an output of the frequency-domain filter.
35. The medium according to claim 34 wherein the method comprises varying the response of the frequency-domain filter as a function of frequency.
36. The medium according to any one of claims 31 through 35 wherein the method comprises:
obtaining a measure of tonality of the audio signal represented by the set of subband signals; and adapting the scaling envelope in response to the measure of tonality.
obtaining a measure of tonality of the audio signal represented by the set of subband signals; and adapting the scaling envelope in response to the measure of tonality.
37. The medium according to claim 36 wherein the method obtains the measure of tonality from the input signal.
38. The medium according to claim 36 wherein the method comprises deriving the measure of tonality from the way in which the zero-valued spectral components are arranged in the particular subband signal.
39. The medium according to any one of claims 31 through 38 wherein the synthesis filterbank is implemented by a block transform and the method comprises:
obtaining a sequence of sets of subband signals from the input signal;
identifying a common subband signal in the sequence of sets of subband signals where, for each set in the sequence, one or more spectral components have a non-zero value and a plurality of spectral components have a zero value;
identifying a common spectral component within the common subband signal that has a zero value in a plurality of adjacent sets in the sequence that are either preceded or followed by a set with the common spectral components having a non-zero value;
scaling the synthesized spectral components that correspond to the zero-valued common spectral components according to the scaling envelope that varies from set to set in the sequence according to temporal masking characteristics of the human auditory system;
generating a sequence of modified sets of subband signals by substituting the synthesized spectral components for the corresponding zero-valued common spectral components in the sets; and generating the audio information by applying the synthesis filterbank to the sequence of modified sets of subband signals.
obtaining a sequence of sets of subband signals from the input signal;
identifying a common subband signal in the sequence of sets of subband signals where, for each set in the sequence, one or more spectral components have a non-zero value and a plurality of spectral components have a zero value;
identifying a common spectral component within the common subband signal that has a zero value in a plurality of adjacent sets in the sequence that are either preceded or followed by a set with the common spectral components having a non-zero value;
scaling the synthesized spectral components that correspond to the zero-valued common spectral components according to the scaling envelope that varies from set to set in the sequence according to temporal masking characteristics of the human auditory system;
generating a sequence of modified sets of subband signals by substituting the synthesized spectral components for the corresponding zero-valued common spectral components in the sets; and generating the audio information by applying the synthesis filterbank to the sequence of modified sets of subband signals.
40. The medium according to any one of claims 31 through 39 wherein the synthesis filterbank is implemented by a block transform and the method generates the synthesized spectral components by spectral translation of other spectral components in the set of subband signals.
41. The medium according to any one of claims 31 through 40 wherein the scaling envelope varies according to temporal masking characteristics of the human auditory system.
42. A medium that conveys a program of instructions and is readable by a device for executing the program of instructions to perform a method for generating an output signal, wherein the method comprises:
generating a set of subband signals each having one or more spectral components representing spectral content of an audio signal by quantizing information that is obtained by applying an analysis filterbank to audio information;
identifying within the set of subband signals a particular subband signal in which one or more spectral components have a non-zero value and are quantized by a quantizer having a minimum quantizing level that corresponds to a threshold, and in which a plurality of spectral components have a zero value;
deriving scaling control information from the spectral content of the audio signal, wherein the scaling control information controls scaling of synthesized spectral components to be synthesized and substituted for the spectral components having a zero value in a receiver that generates audio information in response to the output signal; and generating the output signal by assembling the scaling control information and information representing the set of subband signals.
generating a set of subband signals each having one or more spectral components representing spectral content of an audio signal by quantizing information that is obtained by applying an analysis filterbank to audio information;
identifying within the set of subband signals a particular subband signal in which one or more spectral components have a non-zero value and are quantized by a quantizer having a minimum quantizing level that corresponds to a threshold, and in which a plurality of spectral components have a zero value;
deriving scaling control information from the spectral content of the audio signal, wherein the scaling control information controls scaling of synthesized spectral components to be synthesized and substituted for the spectral components having a zero value in a receiver that generates audio information in response to the output signal; and generating the output signal by assembling the scaling control information and information representing the set of subband signals.
43. The medium according to claim 42 wherein the method comprises:
obtaining a measure of tonality of the audio signal represented by the set of subband signals; and deriving the scaling control information from the measure of tonality.
obtaining a measure of tonality of the audio signal represented by the set of subband signals; and deriving the scaling control information from the measure of tonality.
44. The medium according to claim 42 or 43 wherein the method comprises:
obtaining an estimated psychoacoustic masking threshold of the audio signal represented by the set of subband signals; and deriving the scaling control information from the estimated psychoacoustic masking threshold.
obtaining an estimated psychoacoustic masking threshold of the audio signal represented by the set of subband signals; and deriving the scaling control information from the estimated psychoacoustic masking threshold.
45. The medium according to any one of claims 42 through 44 wherein the method comprises:
obtaining two measures of spectral levels for portions of the audio signal represented by the non-zero-valued and the zero-valued spectral components; and deriving the scaling control information from the two measures of spectral levels.
obtaining two measures of spectral levels for portions of the audio signal represented by the non-zero-valued and the zero-valued spectral components; and deriving the scaling control information from the two measures of spectral levels.
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CA2735830A CA2735830C (en) | 2002-06-17 | 2003-05-30 | Audio coding system using spectral hole filling |
CA2736046A CA2736046A1 (en) | 2002-06-17 | 2003-05-30 | Audio coding system using spectral hole filling |
CA2736055A CA2736055C (en) | 2002-06-17 | 2003-05-30 | Audio coding system using spectral hole filling |
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
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US10/174,493 | 2002-06-17 | ||
US10/174,493 US7447631B2 (en) | 2002-06-17 | 2002-06-17 | Audio coding system using spectral hole filling |
PCT/US2003/017078 WO2003107328A1 (en) | 2002-06-17 | 2003-05-30 | Audio coding system using spectral hole filling |
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CA2736055A Division CA2736055C (en) | 2002-06-17 | 2003-05-30 | Audio coding system using spectral hole filling |
CA2736046A Division CA2736046A1 (en) | 2002-06-17 | 2003-05-30 | Audio coding system using spectral hole filling |
CA2735830A Division CA2735830C (en) | 2002-06-17 | 2003-05-30 | Audio coding system using spectral hole filling |
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CA2489441A1 true CA2489441A1 (en) | 2003-12-24 |
CA2489441C CA2489441C (en) | 2012-04-10 |
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CA2736046A Abandoned CA2736046A1 (en) | 2002-06-17 | 2003-05-30 | Audio coding system using spectral hole filling |
CA2489441A Expired - Lifetime CA2489441C (en) | 2002-06-17 | 2003-05-30 | Audio coding system using spectral hole filling |
CA2736055A Expired - Lifetime CA2736055C (en) | 2002-06-17 | 2003-05-30 | Audio coding system using spectral hole filling |
CA2735830A Expired - Lifetime CA2735830C (en) | 2002-06-17 | 2003-05-30 | Audio coding system using spectral hole filling |
CA2736065A Expired - Lifetime CA2736065C (en) | 2002-06-17 | 2003-06-09 | Audio coding system using characteristics of a decoded signal to adapt synthesized spectral components |
CA2736060A Expired - Lifetime CA2736060C (en) | 2002-06-17 | 2003-06-09 | Audio coding system using characteristics of a decoded signal to adapt synthesized spectral components |
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CA2736046A Abandoned CA2736046A1 (en) | 2002-06-17 | 2003-05-30 | Audio coding system using spectral hole filling |
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CA2736055A Expired - Lifetime CA2736055C (en) | 2002-06-17 | 2003-05-30 | Audio coding system using spectral hole filling |
CA2735830A Expired - Lifetime CA2735830C (en) | 2002-06-17 | 2003-05-30 | Audio coding system using spectral hole filling |
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