Encoding decoding and compression of audio-type data using reference coefficients located within a band of coefficients

Abstract

An audio type signal is encoded. The signal is first divided into bands. For each band, a yardstick signal element is selected. The yardstick may be the signal element having the largest magnitude in the band, the second largest, closest to the median magnitude, or having some other selected magnitude. This magnitude is used for various purposes, including assigning bits to the different bands, and for establishing reconstruction levels within a band. The magnitude of non yardstick signal elements is also quantized. The encoded signal is also decoded. Apparatus for both encoding and decoding are also disclosed. The location of the yardstick element within its band may also be recorded and encoded, and used for efficiently allocating bits to non-yardstick signal elements. Split bands may be established, such that each split band includes a yardstick signal element and each full band includes a major and a minor yardstick signal element.

1. A method for encoding a selected aspect of a signal that is defined by signal elements that are discrete in at least one dimension, said method comprising the steps of:
 a. dividing the signal into at least one band, at least one of said at least one band(s) having a plurality of adjacent signal elements;  
 b. in at least one band, identifying a signal element having a magnitude with a preselected size relative to other signal elements in said at least one band(s) and designating said signal element as a “yardstick” signal element for said at least one band(s); and  
 c. encoding the location of at least one yardstick signal element(s) with respect to its position along said at least one dimension in which said signal elements are discrete within its respective band.  
 
     
     
       2. The method of  claim 1 , further comprising the step of quantizing the magnitude of said at least one yardstick signal element(s) for which the location was encoded. 
     
     
       3. The method of  claim 2 , at least one of said yardstick signal elements having a magnitude that is greater than the magnitude of any other signal element in its respective band. 
     
     
       4. The method of  claim 2 , at least one of said yardstick signal elements having a magnitude that is greater than the magnitude of all but one other signal elements in its respective band. 
     
     
       5. The method of  claim 2 , at least one of said yardstick signal elements having a magnitude that is greater than the magnitude of all but a preselected number of other signal elements in its respective band. 
     
     
       6. A method for decoding a code representing a selected aspect of a signal that is defined by signal elements that are discrete in at least one dimension, which code has been encoded by a method comprising the steps of:
 a. dividing the signal into at least one band, at least one of said at least one band(s) having a plurality of adjacent signal elements;  
 b. in at least one band, identifying a signal element having a magnitude with a preselected size relative to other signal elements in said at least one band(s) and designating said signal element as a “yardstick” signal element for said at least one band(s);  
 c. encoding the location of at least one yardstick signal element(s) with respect to its position along said at least one dimension in which said signal elements are discrete within its respective band;  
 d. quantizing the magnitude(s) of said at least one yardstick signal element(s) for which the location was encoded; and  
 e. using a function of said encoded location(s) and magnitude(s) of said at least one yardstick signal element(s) to encode said selected aspect of said signal;  
 
       said method of decoding comprising the step of translating said code based on a function that is appropriately inversely related to said function of the location(s) and magnitude(s) used to encode said code. 
     
     
       7. An apparatus for encoding a selected aspect of a signal that is defined by signal elements that are discrete in at least one dimension, said apparatus comprising:
 a. means for dividing the signal into at least one band, at least one of said at least one band(s) having a plurality of adjacent signal elements;  
 b. in at least one band, means for identifying a signal element having a magnitude with a preselected size relative to other signal elements in said at least one band(s) and means for designating said signal element as a “yardstick” signal element for said band;  
 c. means for encoding the location of at least one yardstick signal element(s) with respect to its position along said at least one dimension in which said signal elements are discrete within its respective band; and  
 d. means for quantizing the magnitude of said at least one yardstick signal element(s) for which the location was encoded.  
 
     
     
       8. An apparatus for decoding a code representing a selected aspect of a signal that is defined by signal elements that are discrete in at least one dimension, which code has been encoded by an apparatus comprising:
 a. means for dividing the signal into at least one band, at least one of said at least one band(s) having a plurality of adjacent signal elements;  
 b. means for, in at least one band, identifying a signal element having a magnitude with a preselected size relative to other signal elements in said at least one band(s) and designating said signal element as a “yardstick” signal element for said at least one band(s);  
 c. means for encoding the location of at least one yardstick signal element(s) with respect to its position along said at least one dimension in which said signal elements are discrete within its respective band;  
 d. means for quantizing the magnitude of said at least one yardstick signal element(s) for which the location was encoded; and  
 e. means for using a function of said encoded location and magnitude of said at least one yardstick signal element(s) to encode said selected aspect of said signal;  
 
       said decoding apparatus comprising:
 i. a yardstick location decoder; and  
 ii. a code transistor that applies a translating rule that is appropriately inversely related to said function of the location and magnitude used to encode said selected aspect of said signal.  
 
     
     
       9. A method of encoding a signal defined by signal elements that are discrete in at least one dimension, the method comprising:
   dividing at least some of the signal elements into a plurally of bands, at least one band having a plurality of adjacent signal elements;        selecting a signal element from each of more than one of the bans, at least one of the selected signal elements being from one of the bands having a plurality of adjacent signal elements; and        performing a transformation on the selected signal elements.     
     
     
       10. The method of  claim 9  wherein selecting the signal element comprises identifying the signal element having a preselected size related to the other signal elements within a band. 
     
     
       11. The method of  claim 9  wherein performing a transformation comprises performing a transformation on the magnitudes of the selected signal elements. 
     
     
       12. The method of  claim 9  wherein the signal elements comprise samples of a signal. 
     
     
       13. The method of  claim 9  wherein the signal elements comprise transform coefficients. 
     
     
       14. The method of  claim 13  wherein the transform coefficients comprise transform coefficients derived from a frame obtained by applying a window to samples of a signal. 
     
     
       15. The method of  claim 13  wherein the transform coefficients correspond to at least one of the following: discrete cosine transform coefficients and time- domain aliasing cancellation coefficients.   
     
     
       16. The method of  claim 9  wherein performing the transformation comprises using a transformation that reduces the average number of bits needed to encode the selected signal elements. 
     
     
       17. The method of  claim 9  further comprising quantizing results of the transformation. 
     
     
       18. The method of  claim 17  further comprising using the quantized results of the transformation to encode signal elements. 
     
     
       19. The method of  claim 18  wherein using the quantized results of the transformation comprises allocating bits to signal elements. 
     
     
       20. The method of  claim 9  further comprising using the selected signal elements to encode signal elements. 
     
     
       21. A method of encoding a signal defined by signal elements that are discrete in at least one dimension, the method comprising:
   dividing at least some of the signal elements into a plurality of bands, at least one band having a plurality of adjacent signal elements;        selecting a signal element from each of more than one of the bands, at least one of the selected signal elements being from one of the bands having a plurality of adjacent signal elements;        processing the selected signal elements; and        performing a transformation on the processed selected signal elements.     
     
     
       22. The method of  claim 21  wherein the processing comprises quantizing. 
     
     
       23. The method of  claim 22  wherein the quantizing comprises quantizing the magnitudes of the selected signal elements. 
     
     
       24. The method of  claim 23  wherein the quantizing the magnitudes of the selected signal elements comprises quantizing the magnitudes using exponents associated with the magnitudes. 
     
     
       25. The method of  claim 21  wherein the processing comprises a non- linear mapping.   
     
     
       26. The method of  claim 21  wherein selecting the signal element comprises identifying the signal elements having the largest magnitude within a band. 
     
     
       27. The method of  claim 21  wherein selecting the signal element comprises identifying the signal element having a preselected size of magnitude relative to other signal elements within a band. 
     
     
       28. The method of  claim 21  wherein performing the transformation comprises performing at least one of the following: a discrete cosine transformation and a discrete Fourier transformation. 
     
     
       29. The method of  claim 21  wherein the signal elements comprise transform coefficients. 
     
     
       30. The method of  claim 29  wherein the transform coefficients comprise transform coefficients derived from a frame obtained by applying a window to samples of a signal. 
     
     
       31. The method of  claim 29  wherein the transform coefficients correspond to at least one of the following: discrete cosine transform coefficients and time- domain aliasing cancellation coefficients.   
     
     
       32. The method of  claim 21  wherein performing the transformation comprises using a transformation that reduces the average number of bits needed to encode the processed selected signal elements. 
     
     
       33. The method of  claim 21  further comprising using the processed selected signal elements to encode signal elements. 
     
     
       34. The method of  claim 33  wherein using the processed selected signal elements to encode signal elements comprises using the processed selected signal elements to encode signal elements in the respective bands of the selected signal elements. 
     
     
       35. The method of  claim 33  wherein using the processed selected signal elements to encode signal elements comprises allocating bits to the signal elements. 
     
     
       36. The method of  claim 31  wherein using the processed selected signal elements to encode signal elements comprises determining reconstruction levels for signal elements. 
     
     
       37. A method of encoding a signal defined by signal elements that are discrete in at least one dimension, the signal elements comprising transform coefficients obtained using samples of the signal, the method comprising:
   dividing at least some of the signal elements into a plurality of bands, at least one band having a plurality of adjacent signal elements;        selecting a signal element from each of more than one of the bans, the selected signal element having a preselected size of magnitude relative to the other signal elements within one of the bands, at least one of the selected signal elements being from one of the bands having a plurality of adjacent signal elements;        processing the selected signal elements, the processing including quantizing the magnitudes of the selected signal elements; and        transforming the processed selected signal elements using a transformation that reduces the average number of bits needed to encode the processed selected signal elements.     
     
     
       38. The method of  claim 37  further comprising encoding the transformed processed selected signal elements. 
     
     
       39. A method of decoding, comprising:
   receiving an encoded signal, the signal being defined by signal elements that are discrete in at least one dimension, the encoded signal of the type encoded by:      dividing at least some of the signal elements into a plurality of bands, at least one band having a plurality of adjacent signal elements;        selecting a signal element from each of more than one of the bands, at least one of the selected signal elements being from one of the bands having a plurality of adjacent signal elements; and        performing a transformation on the selected signal elements; and        decoding at least some of the received encoded signal, the decoding comprising performing an inverse transformation.       
     
     
       40. The method of  claim 39  wherein performing an inverse transformation comprises performing an inverse transformation on the transformed selected signal elements. 
     
     
       41. The method of  claim 39  wherein performing the inverse transformation comprises performing at least one of the following: an inverse discrete Fourier transformation and an inverse discrete cosine transformation. 
     
     
       42. The method of  claim 39  wherein decoding comprises using results of the inverse transformation to decode signal elements. 
     
     
       43. The method of  claim 39  wherein the signal elements comprise transform coefficients. 
     
     
       44. The method of  claim 43  wherein the transform coefficients comprise transform coefficients derived from a frame obtained by applying a window to samples of a signal. 
     
     
       45. A method of decoding, comprising:
   receiving an encoded signal, the signal being defined by signal elements that are discrete in at least one dimension, the encoded signal of the type encoded by:      dividing at least some of the signal elements into a plurality of bands, at least one band having a plurality of adjacent signal elements;        selecting a signal element from each of more than one of the bands, at least one of the selected signal elements being from one of the bands having a plurality of adjacent signal elements;        processing the selected signal elements; and        performing a transformation on the processed selected signal elements; and        decoding at least one of the received signal, the decoding comprising performing an inverse transformation.       
     
     
       46. The method of  claim 45  wherein the performing an inverse transformation comprises performing an inverse transformation on the transformed processed selected signal elements. 
     
     
       47. The method of  claim 45  wherein the processing comprises quantizing the magnitudes of the selected signal elements. 
     
     
       48. The method of  claim 47  wherein the quantizing the magnitudes of the selected signal elements comprises quantizing the magnitudes using exponents associated with the magnitudes. 
     
     
       49. The method of  claim 45  wherein the processing comprises a non- linear mapping.   
     
     
       50. The method of  claim 45  wherein decoding comprises using results of the inverse transformation to decode signal elements. 
     
     
       51. The method of  claim 50  wherein using results of the inverse transformation comprises using the results to decode the signal elements from the respective bands of the selected signal elements. 
     
     
       52. The method of  claim 50  wherein using the results of the inverse transformation comprises determining reconstruction levels for signal elements. 
     
     
       53. The method of  claim 45  wherein the signal elements comprise transform coefficients. 
     
     
       54. The method of  claim 53  wherein the transform coefficients comprise transform coefficients derived from a frame obtained by applying a window to samples of a signal. 
     
     
       55. The method of  claim 53  wherein decoding further comprises performing an inverse transformation on the decoded signal elements. 
     
     
       56. A method of encoding a signal defined by transform coefficients that are discrete in at least one dimension, the method comprising:
   determining a division of at least some of the transform coefficients into a plurality of bands, at least one of the bands having a plurality of adjacent transform coefficients; and        providing information describing the determined division.     
     
     
       57. The method of  claim 56  wherein providing information describing the determined division comprises encoding information describing the determined division. 
     
     
       58. The method of  claim 57  further comprising encoding at least some of the transform coefficients using the determined division. 
     
     
       59. The method of  claim 57  wherein the determining comprises dividing based on at least one signal characteristic. 
     
     
       60. The method of  claim 59  wherein the at least one signal characteristic comprises a magnitude of at least one transform coefficient. 
     
     
       61. The method of  claim 59  wherein the at least one signal characteristic comprises a difference between transform coefficients. 
     
     
       62. The method of  claim 61  wherein the difference comprises a difference in transform coefficient magnitudes. 
     
     
       63. The method of  claim 57  wherein the determining comprises beginning a new band when adjacent transform coefficients significantly differ in magnitude. 
     
     
       64. The method of  claim 57  wherein the determining comprises dividing the transform coefficients such that at least one band has a number of transform coefficients that is a power of two. 
     
     
       65. The method of  claim 57  wherein the determining comprises dividing the transform coefficients such that at least two bands include a different number of signal elements. 
     
     
       66. The method of  claim 57  wherein the encoding information describing the dividing comprises encoding the number of transform coefficients included in at least one band. 
     
     
       67. The method of  claim 57  wherein the transform coefficients comprise transform coefficients derived from a frame obtained by applying a window to samples of a signal. 
     
     
       68. The method of  claim 57  wherein the transform coefficients comprise at least one of the following: discrete cosine transform coefficients and time- domain aliasing cancellation coefficients.   
     
     
       69. The method of  claim 57  wherein the determining differs for different signals. 
     
     
       70. The method of  claim 57  wherein the determining differs for different frames. 
     
     
       71. A method of decoding, comprising:
   receiving an encoded signal, the signal being defined by transform coefficients that are discrete in at least one dimension, the encoded signal of the type encoded by:      determining a division of at least some of the transform coefficients into a plurality of bands, at least one of the bands having a plurality of adjacent transform coefficients; and        encoding information describing the determined division; and          decoding at least part of an encoded signal, the decoding comprising using the received encoded information describing the determined division.     
     
     
       72. The method of  claim 71  wherein the information describing the division comprises information based on at least one characteristic of an encoded signal. 
     
     
       73. The method of  claim 72  wherein the at least one signal characteristic comprises a magnitude of at least one transform coefficient. 
     
     
       74. The method of  claim 72  wherein the at least one signal characteristic comprises a difference between transform coefficients. 
     
     
       75. The method of  claim 71  wherein the division comprises a division of the transform coefficients such that at least two bands include a different number of transform coefficients. 
     
     
       76. The method of  claim 71  wherein the information comprises the number of transform coefficients included in at least one band. 
     
     
       77. The method of  claim 71  wherein the transform coefficients comprise transform coefficients derived from a frame obtained by applying a window to samples of a signal. 
     
     
       78. The method of  claim 71  wherein the transform coefficients comprise at least one of the following: discrete cosine transform coefficients and time- domain aliasing cancellation coefficients.   
     
     
       79. The method of  claim 71  wherein the information differs for different signals. 
     
     
       80. The method of  claim 71  wherein the information differs for different frames. 
     
     
       81. A method of encoding a signal defined by signal elements that are discrete in at least one dimension, the method comprising:
   dividing at least some of the signal elements into a plurality of bands, at least one band having a plurality of adjacent signal elements;        selecting a signal element from each of more than one of the bands, at least one of the selected signal elements being from one of the bands having a plurality of signal elements;        processing the selected signal elements;        performing a transformation on the processed selected signal elements;        encoding the transformed processed selected signal elements; and        encoding information describing the dividing.     
     
     
       82. The method of  claim 81  wherein selecting the signal element comprises identifying the signal element having a preselected size of magnitude relative to the other signal elements within a band. 
     
     
       83. The method of  claim 81  wherein processing the selected signal elements comprises quantizing. 
     
     
       84. The method of  claim 83  wherein quantizing comprises quantizing magnitudes of the selected signal elements. 
     
     
       85. The method of  claim 84  wherein the quantizing the magnitudes of the selected signal elements comprises quantizing the magnitudes using exponents associated with the magnitudes. 
     
     
       86. The method of  claim 81  wherein the signal elements comprise transform coefficients. 
     
     
       87. The method of  claim 86  wherein the transform coefficients comprise transform coefficients derived from a frame obtained by applying a window to samples of a signal. 
     
     
       88. The method of  claim 86  wherein the transform coefficients correspond to at least one of the following: discrete cosine transform coefficients and time- domain aliasing cancellation coefficients.   
     
     
       89. The method of  claim 81  further comprising using the processed selected signal elements to encode signal elements. 
     
     
       90. The method of  claim 81  wherein the encoding information describing the dividing comprises encoding the number of signal elements included in at least one band. 
     
     
       91. A method of decoding, comprising:
   receiving an encoded signal, the signal being defined by signal elements that are discrete in at least one dimension, the encoded signal of the type encoded by:      dividing at least some of the signal elements into a plurality of bands, at least one band having a plurality of adjacent signal elements;        selecting a signal element from each of more than one of the bands, at least one of the selected signal elements being from one of the bands having a plurality of signal elements;        processing the selected signal elements;        performing a transformation on the processed selected signal elements;        encoding the transformed processed selected signal elements; and        encoding information describing the dividing; and          decoding at least some of the received encoded signal, the decoding comprising:      using the information describing the dividing; and        performing an inverse transformation.       
     
     
       92. The method of  claim 91  wherein performing an inverse transformation comprises performing an inverse transformation on the transformed processed selected signal elements. 
     
     
       93. The method of  claim 91  wherein selecting the signal element comprises identifying the signal element having the largest magnitude within a band. 
     
     
       94. The method of  claim 91  wherein selecting the signal element comprises identifying the signal element having a preselected size of magnitude relative to the other signal elements within a band. 
     
     
       95. The method of  claim 91  wherein the signal elements comprise transform coefficients. 
     
     
       96. The method of  claim 95  wherein the transform coefficients comprise transform coefficients derived from a frame obtained by applying a window to samples of a signal. 
     
     
       97. The method of  claim 95  wherein the transform coefficients correspond to at least one of the following: discrete cosine transform coefficients and time- domain aliasing cancellation coefficients.   
     
     
       98. The method of  claim 91  further comprising using the selected signal elements to encode signal elements. 
     
     
       99. The method of  claim 91  wherein the encoding information describing the dividing comprises encoding the number of signal elements included in at least one band. 
     
     
       100. A method of encoding an audio- type signal, the method comprising:      sampling the audio - type signal to obtain discrete samples and costructing therefrom frames, each frame obtained by applying a window to the discrete samples;        determining a set of transform coefficients from each of at least some of the frames; and        for each of at least some of the sets of transform coefficients:      dividing at least some of the transform coefficients into a plurality of bands, at least one band having a plurality of adjacent transform coefficients;        selecting a transform coefficient from each of more than one of the bands, at least one of the selected transform coefficients being from one of the bands having a plurality of adjacent transform coefficients;        processing the selected transform coefficients; and        performing a transformation on the processed selected transform coefficients.       
     
     
       101. The method of  claim 100  wherein processing comprises quantizing the magnitude of the selected transform coefficients. 
     
     
       102. The method of  claim 100  wherein selecting the transform coefficient comprises identifying the transform coefficient having a preselected size relative to other transform coefficient within a band. 
     
     
       103. A method of encoding an audio- type signal, the method comprising:      sampling the audio - type signal to obtain discrete samples and constructing therefrom frames, each frame obtained by applying a window to the discrete samples;        determining a set of transform coefficients from each of at least some of the frames;        for each of at least some of the sets of transform coefficients:      dividing at least some of the transform coefficients into a plurality of bands, at least one band having a plurality of adjacent transform coefficients; and        encoding the dividing.       
     
     
       104. The method of  claim 103  further comprising encoding at least some of the transform coefficients using the determined division. 
     
     
       105. The method of  claim 103  wherein the dividing differs for different frames. 
     
     
       106. A method of decoding an audio- type signal, the method comprising:      receiving an encoded audio - type signal, the encoded signal of the type encoded by:      sampling the audio - type signal to obtain discrete samples and constructing therefrom frames, each frame obtained by applying a window to the discrete samples;        determining a set of transform coefficients from each of at least some of the frames;        for each of at least some of the sets of transform coefficients:      dividing at least some of the transform coefficients into a plurality of bands, at least one band having a plurality of adjacent transform coefficient;        selecting a transform coefficient from each of more than one of the bands, at least one of the selected transform coefficients being from one of the bands having a plurality of adjacent transform coefficients;        processing the selected transform coefficients; and        performing a transformation on the processed selected transform coefficients; and            decoding the received encoded audio - type signal, the decoding comprising performing an inverse transformation.     
     
     
       107. The method of  claim 106  wherein performing an inverse transformation comprises performing an inverse transformation on the transformed processed selected transform coefficients. 
     
     
       108. The method of  claim 106  wherein processing comprises quantizing the magnitudes of the selected transform coefficients. 
     
     
       109. The method of  claim 106  wherein selecting the transform coefficient comprises identifying the transform coefficient having a preselected size relative to other transform coefficients within a band. 
     
     
       110. A method of decoding an audio- type signal, the method comprising:      receiving an encoded audio - type signal, the encoded signal of the type encoded by:      sampling the audio - type signal to obtain discrete samples and constructing therefrom frames, each frame obtained by applying a window to the discrete samples;        determining a set of transform coefficients from each of at least some of the frames;        for each of at least some of the sets of transform coefficients:      dividing at least some of the transform coefficients into a plurality of bands, at least one band having a plurality of adjacent transform coefficients; and        encoding the dividing; and            decoding the received encoded audio - type signal, the decoding comprising decoding the dividing.     
     
     
       111. The method of  claim 110  further comprising decoding at least some of the transform coefficients using the decoded division. 
     
     
       112. The method of  claim 110  wherein the dividing differs for different frames. 
     
     
       113. A method of encoding an audio- type signal, the method comprising:      sampling the audio - type signal to obtain discrete samples and constructing therefrom frames, each frame obtained by applying a window to the discrete samples;        determining a set of transform coefficients from each of at least some of the frames;        for each of at least some of the sets of transform coefficients:      dividing at least some of the transform coefficients into a plurality of bands, at least one band having a plurality of adjacent transform coefficients;        selecting a transform coefficient from each of more than one of the bands, at least one of the selected transform coefficients being from one of the bands having a plurality of adjacent transform coefficients;        processing the selected transform coefficients;        performing a transformation on the processed selected transform coefficients; and        encoding the dividing.       
     
     
       114. A method of decoding an audio- type signal, the method comprising:      receiving an encoded audio - type signal, the encoded signal of the type encoded by;      sampling the audio - type signal to obtain discrete samples and constructing therefrom frames, each frame obtained by applying a window to the discrete samples;        determining a set of transform coefficients from each of at least some of the frames;        for each of at least some of the sets of transform coefficients:      dividing at least some of the transform coefficients into a plurality of bands, at least one band having a plurality of adjacent transform coefficients;        selecting a transform coefficient from each of more than one of the bands, at least one of the selected transform coefficients being from one of the bands having plurality of adjacent transform coefficients;        processing the selected transform coefficients;        performing a transformation on the processed selected transform coefficients; and        encoding the dividing; and            decoding the encoded audio - type signal, the decoding comprising:      performing an inverse transformation; and        decoding the dividing.