Patent US5311561A successfully refreshed from Google Patents.
US5311561A
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Method and apparatus for compressing a digital input signal with block floating applied to blocks corresponding to fractions of a critical band or to multiple critical bands
Assignee: Sony Corp
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Filing: 1992-03-26
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Granted: 1994-05-10
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Expires: 2012-03-26
Abstract
Abstract A method for compressing a digital input signal to provide a compressed signal in which spectral components are derived from the digital input signal and are divided into critical bands. The spectral components at lower frequencies are also divided into a block having a bandwidth corresponding to that of plural critical bands. Block floating processing is applied to the block to generate a floating coefficient. Finally, the spectral components in each critical band are quantized using an adaptively-allocated number of bits. Additionally, the word length indicating the number of bits allocated for quantizing the spectral components in each critical band is included in the compressed signal together with the floating coefficient for the block as the only floating coefficient for the critical bands in the block. This reduces the number of bits in the compressed signal. The spectral components in a higher-frequency critical band are divided into blocks having a bandwidth that is narrower than the bandwidth of the critical band. Block floating processing is applied to the blocks to generate a floating coefficient for each block. Finally, the spectral components in each block are quantized using an adaptively-allocated number of bits. The word length for each block is included in the compressed signal together with, instead of the floating coefficient for each block, the allowed noise level for the critical band.
Inventors
- 👤 Kenzo Akagiri
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 10:36
CPC Classifications
H; H03; H03M; H03M7/00; H03M7/30; H04; H04B; H04B1/00; H04B1/66; H04B1/665
Claims Analysis
Total Claims: 56
Claim 1
Independent Claim
133 words
A method for compressing a digital input signal to provide a compressed signal, the method comprising the steps of: deriving spectral components from the digital input signal; dividing the spectral components into critical bands; dividing the spectral components in a critical band into blocks having a bandwidth narrower than the critical band; applying block floating processing to the blocks to generate a floating coefficient for each block; quantizing the spectral components in each block using a number of bits allocated to the block according to an allowed noise level for the critical band, the number of bits allocated being indicated by a word length; and including in the compressed signal the word length for each block, and, instead of the floating coefficient for each block, the allowed noise level for the critical band.
Claim 2
Independent Claim
133 words
A method for compressing a digital input signal to provide a compressed signal, the method comprising the steps of: deriving spectral components from the digital input signal; dividing the spectral components into critical bands; dividing the spectral components in a critical band into blocks having a bandwidth narrower than the critical band; applying block floating processing to the blocks to generate a floating coefficient for each block; quantizing the spectral components in each block using a number of bits allocated to the block according to an allowed noise level for the critical band, the number of bits allocated being indicated by a word length; and including in the compressed signal the word length for each block, and, instead of the floating coefficient for each block, the allowed noise level for the critical band.
Claim 3
Dependent Claim
36 words
The method of claim 1, wherein, in the step of deriving spectral components from the digital input signal, the spectral components are derived by orthogonally transforming the digital input signal using a discrete cosine transform (DCT).
Claim 4
Dependent Claim
47 words
The method of claim 1, wherein, in the step of dividing the spectral components into critical bands, spectral components in a frequency range of 0 Hz to 22 kHz are divided into 25 critical bands having a bandwidth that broadens with increasing frequency of the critical band.
Claim 5
Dependent Claim
77 words
The method of claim 1, wherein: the step of quantizing the spectral components in each block includes the steps of: calculating the allowed noise level from the spectral components, and calculating a magnitude for each block from the spectral components in the block; and in the step of quantizing the spectral components in each block, the number of bits is allocated according to a level difference between the magnitude for the block and the allowed noise level.
Claim 6
Dependent Claim
51 words
The method of claim 4, wherein: the step of deriving spectral components from the digital input signal provides spectral components having amplitude information and phase information; and the step of calculating a magnitude for each block calculates the magnitude by summing the amplitude information of the spectral components in the block.
Claim 7
Dependent Claim
57 words
The method of claim 5, wherein the step of calculating the allowed noise level includes the steps of: calculating a magnitude for each critical band by summing the amplitude information of the spectral components in each respective critical band; and convoluting the magnitude for each critical band with a predetermined weighting function to take account of masking.
Claim 8
Dependent Claim
41 words
The method of claim 1, wherein, in the including step: the allowed noise level included in the compressed signal is coarsely quantized; and additional bits for each block are included in the compressed signal to finely quantize the allowed noise level.
Claim 9
Dependent Claim
51 words
The method of claim 7, wherein, in the including step: the allowed noise level included in the compressed signal is coarsely quantized using a first number of bits; and a second number of additional bits for each block is included in the compressed signal to finely quantize the allowed noise level.
Claim 10
Dependent Claim
25 words
The method of claim 7, wherein, in the including step: the first number of bits is four; and the second number of bits is two.
Claim 11
Dependent Claim
24 words
The method of claim 7, wherein, in the including step, the coarse quantizing and the fine quantizing of the allowed noise level are logarithmic.
Claim 12
Independent Claim
76 words
A method for compressing a digital input signal to provide a compressed signal, the method comprising the steps of: deriving spectral components from the digital input signal; dividing the spectral components into critical bands; dividing the spectral components into a block having a bandwidth corresponding to plural critical bands; applying block floating processing to the block to generate a floating coefficient; and quantizing the spectral components in each critical band using an adaptively-allocated number of bits.
Claim 13
Independent Claim
76 words
A method for compressing a digital input signal to provide a compressed signal, the method comprising the steps of: deriving spectral components from the digital input signal; dividing the spectral components into critical bands; dividing the spectral components into a block having a bandwidth corresponding to plural critical bands; applying block floating processing to the block to generate a floating coefficient; and quantizing the spectral components in each critical band using an adaptively-allocated number of bits.
Claim 14
Dependent Claim
36 words
The method of claim 11, wherein, in the step of deriving spectral components from the digital input signal, the spectral components are derived by orthogonally transforming the digital input signal using a discrete cosine transform (DCT).
Claim 15
Dependent Claim
47 words
The method of claim 11, wherein, in the step of dividing the spectral components into critical bands, spectral components in a frequency range of 0 Hz to 22 kHz are divided into 25 critical bands having a bandwidth that broadens with increasing frequency of the critical band.
Claim 16
Dependent Claim
39 words
The method of claim 13, wherein, in the step of dividing the spectral components into a block having a bandwidth corresponding to plural critical bands, the spectral components in the block are at low frequencies in the frequency range.
Claim 17
Dependent Claim
77 words
The method of claim 11, wherein: in the step of quantizing the spectral components in each critical band using an adaptively-allocated number of bits, the adaptively-allocated number of bits is indicated by a word length; and the method additionally comprises the step of including in the compressed signal the floating coefficient for the block as the only floating coefficient for the critical bands in the block, and the word length for each critical band in the block.
Claim 18
Dependent Claim
76 words
The method of claim 15, wherein the step of quantizing the spectral components comprises the steps of: calculating a magnitude for each critical band from the spectral components in the critical band; calculating an allowed noise level for each critical band from the spectral components; and calculating the adaptively-allocated number of bits for each critical band from a level difference between the magnitude for the critical band and the allowed noise level for the critical band.
Claim 19
Dependent Claim
53 words
The method of claim 15, wherein: the step of deriving spectral components from the digital input signal provides spectral components having amplitude information and phase information; and the step of calculating a magnitude for each critical band calculates the magnitude by summing the amplitude information of the spectral components in the critical band.
Claim 20
Dependent Claim
34 words
The method of claim 17, wherein the step of quantizing the spectral components includes the step of convoluting the magnitude of each critical band with a predetermined weighting function to take account of masking.
Claim 21
Independent Claim
81 words
A method for compressing a digital input signal to provide a compressed signal, the method comprising the steps of: deriving spectral components from the digital input signal; dividing the spectral components into critical bands; dividing the spectral components in a critical band into blocks having a bandwidth narrower than the critical band; applying block floating processing to the blocks to generate a floating coefficient for each block; and quantizing the spectral components in each block using an adaptively-allocated number of bits.
Claim 22
Independent Claim
81 words
A method for compressing a digital input signal to provide a compressed signal, the method comprising the steps of: deriving spectral components from the digital input signal; dividing the spectral components into critical bands; dividing the spectral components in a critical band into blocks having a bandwidth narrower than the critical band; applying block floating processing to the blocks to generate a floating coefficient for each block; and quantizing the spectral components in each block using an adaptively-allocated number of bits.
Claim 23
Dependent Claim
36 words
The method of claim 19, wherein, in the step of deriving spectral components from the digital input signal, the spectral components are derived by orthogonally transforming the digital input signal using a discrete cosine transform (DCT).
Claim 24
Dependent Claim
47 words
The method of claim 19, wherein, in the step of dividing the spectral components into critical bands, spectral components in a frequency range of 0 Hz to 22 kHz are divided into 25 critical bands having a bandwidth that broadens with increasing frequency of the critical band.
Claim 25
Dependent Claim
41 words
The method of claim 21, wherein, in the step of dividing the spectral components in a critical band into a blocks having a bandwidth narrower than the critical band, the critical band is at a high frequency in the frequency range.
Claim 26
Dependent Claim
71 words
The method of claim 19 wherein: in the step of quantizing the spectral components in each block using an adaptively-allocated number of bits, the adaptively-allocated number of bits is indicated by a word length; and the method additionally comprises the step of including in the compressed signal the word length for one of the blocks in the critical band as the only word length for the blocks in the critical band.
Claim 27
Dependent Claim
72 words
The method of claim 23, wherein the step of quantizing the spectral components in each block comprises the steps of: calculating an allowed noise level for the critical band from the spectral components; calculating a magnitude for each block from the spectral components in the block; and calculating the adaptively-allocated number of bits for each block according to a level difference between the magnitude of the block and the allowed noise level.
Claim 28
Dependent Claim
51 words
The method of claim 24, wherein: the step of deriving spectral components from the digital input signal provides spectral components having amplitude information and phase information; and the step of calculating a magnitude for each block calculates the magnitude by summing the amplitude information of the spectral components in the block.
Claim 29
Dependent Claim
57 words
The method of claim 25, wherein the step of calculating the allowed noise level includes the steps of: calculating a magnitude for each critical band by summing the amplitude information of the spectral components in each respective critical band; and convoluting the magnitude of each critical band with a predetermined weighting function to take account of masking.
Claim 30
Independent Claim
143 words
A method for compressing a digital input signal to provide a compressed signal, the method comprising the steps of: deriving spectral components from the digital input signal; dividing the spectral components into critical bands; dividing the spectral components in a critical band into blocks having a bandwidth narrower than the critical band; applying block floating processing to the blocks to generate a floating coefficient for each block; quantizing the spectral components in each block using a number of bits allocated to the block according to an allowed noise level for the critical band, the number of bits allocated being indicated by a word length; and including the compressed signal, instead of the floating coefficient for each block, the allowed noise level with a range that is shifted downwards in level by a predetermined level from a signal level range in the critical band.
Claim 31
Independent Claim
143 words
A method for compressing a digital input signal to provide a compressed signal, the method comprising the steps of: deriving spectral components from the digital input signal; dividing the spectral components into critical bands; dividing the spectral components in a critical band into blocks having a bandwidth narrower than the critical band; applying block floating processing to the blocks to generate a floating coefficient for each block; quantizing the spectral components in each block using a number of bits allocated to the block according to an allowed noise level for the critical band, the number of bits allocated being indicated by a word length; and including the compressed signal, instead of the floating coefficient for each block, the allowed noise level with a range that is shifted downwards in level by a predetermined level from a signal level range in the critical band.
Claim 32
Dependent Claim
36 words
The method of claim 27, wherein, in the step of deriving spectral components from the digital input signal, the spectral components are derived by orthogonally transforming the digital input signal using a discrete cosine transform (DCT).
Claim 33
Dependent Claim
47 words
The method of claim 27, wherein, in the step of dividing the spectral components into critical bands, spectral components in a frequency range of 0 Hz to 22 kHz are divided into 25 critical bands having a bandwidth that broadens with increasing frequency of the critical band.
Claim 34
Dependent Claim
77 words
The method of claim 27, wherein: the step of quantizing the spectral components in each block includes the steps of: calculating the allowed noise level from the spectral components, and calculating a magnitude for each block from the spectral components in the block; and in the step of quantizing the spectral components in each block, the number of bits is allocated according to a level difference between the magnitude for the block and the allowed noise level.
Claim 35
Dependent Claim
51 words
The method of claim 30, wherein: the step of deriving spectral components from the digital input signal provides spectral components having amplitude information and phase information; and the step of calculating a magnitude for each block calculates the magnitude by summing the amplitude information of the spectral components in the block.
Claim 36
Dependent Claim
57 words
The method of claim 31, wherein the step of calculating the allowed noise level includes the steps of: calculating a magnitude for each critical band by summing the amplitude information of the spectral components in each respective critical band; and convoluting the magnitude for each critical band with a predetermined weighting function to take account of masking.
Claim 37
Independent Claim
145 words
An apparatus for compressing a digital input signal to provide a compressed signal, the apparatus comprising: an orthogonal transform circuit whereto the input signal is connected; means for dividing spectral components from the orthogonal transform circuit into critical bands; means for dividing the spectral components in a critical band into blocks having a bandwidth narrower than the critical band; means for applying block floating processing to the blocks to generate a floating coefficient for each block; means for quantizing the spectral components in each block using a number of bits allocated to the block according to an allowed noise level for the critical band, the number of bits being indicated by a word length; and means for including in the compressed signal the word length for each block, and, instead of the floating coefficient for each block, the allowed noise level for the critical band.
Claim 38
Independent Claim
145 words
An apparatus for compressing a digital input signal to provide a compressed signal, the apparatus comprising: an orthogonal transform circuit whereto the input signal is connected; means for dividing spectral components from the orthogonal transform circuit into critical bands; means for dividing the spectral components in a critical band into blocks having a bandwidth narrower than the critical band; means for applying block floating processing to the blocks to generate a floating coefficient for each block; means for quantizing the spectral components in each block using a number of bits allocated to the block according to an allowed noise level for the critical band, the number of bits being indicated by a word length; and means for including in the compressed signal the word length for each block, and, instead of the floating coefficient for each block, the allowed noise level for the critical band.
Claim 39
Dependent Claim
16 words
The apparatus of claim 33, wherein orthogonally transform circuit includes a discrete cosine transform (DCT) circuit.
Claim 40
Dependent Claim
50 words
The apparatus of claim 34, wherein, the means for dividing the spectral components from the orthogonal transform circuit into critical bands divides spectral components in a frequency range of 0 Hz to 22 kHz into 25 critical bands having a bandwidth that broadens with increasing frequency of the critical band.
Claim 41
Dependent Claim
77 words
The apparatus of claim 33, wherein: the means for quantizing the spectral components in each block includes means for: calculating the allowed noise level from the spectral components, and calculating a magnitude for each block from the spectral components in the block; and the means for quantizing the spectral components in each block allocates the number of bits to each block according to a level difference between the magnitude for the block and the allowed noise level.
Claim 42
Dependent Claim
45 words
The apparatus of claim 36, wherein: the spectral components from the orthogonal transform circuit include amplitude information and phase information; and the means for calculating a magnitude for each block calculated the magnitude by summing the amplitude information of the spectral components in the block.
Claim 43
Dependent Claim
56 words
The apparatus of claim 37, wherein the means for calculating the allowed noise level includes means for: calculating a magnitude for each critical band by summing the amplitude information of the spectral components in each respective critical band; and convoluting the magnitude for each critical band with a predetermined weighting function to take account of masking.
Claim 44
Dependent Claim
52 words
The apparatus of claim 33, wherein: the allowed noise level included in the compressed signal is coarsely quantized using a first number of bits; and the including means is additionally for including in the compressed signal a second number of additional bits for each block to finely quantize the allowed noise level.
Claim 45
Dependent Claim
52 words
The apparatus of claim 30, wherein: the allowed noise level included in the compressed signal is coarsely quantized using a first number of bits; and the including means is additionally for including in the compressed signal a second number of additional bits for each block to finely quantize the allowed noise level.
Claim 46
Dependent Claim
21 words
The apparatus of claim 40, wherein: the first number of bits is four; and the second number of bits is two.
Claim 47
Dependent Claim
20 words
The apparatus of claim 33, wherein the coarse quantization and the fine quantization of the allowed noise level are logarithmic.
Claim 48
Independent Claim
89 words
An apparatus for compressing a digital input signal to provide a compressed signal, the apparatus comprising: an orthogonal transform circuit whereto the digital input signal is connected; means for dividing spectral components from the orthogonal transform circuit into critical bands; means for dividing the spectral components into a block having a bandwidth corresponding to plural critical bands; means for applying block floating processing to the block to generate a block floating coefficient; and means for quantizing the spectral components in each critical band using an adaptively-allocated number of bits.
Claim 49
Independent Claim
89 words
An apparatus for compressing a digital input signal to provide a compressed signal, the apparatus comprising: an orthogonal transform circuit whereto the digital input signal is connected; means for dividing spectral components from the orthogonal transform circuit into critical bands; means for dividing the spectral components into a block having a bandwidth corresponding to plural critical bands; means for applying block floating processing to the block to generate a block floating coefficient; and means for quantizing the spectral components in each critical band using an adaptively-allocated number of bits.
Claim 50
Dependent Claim
17 words
The apparatus of claim 43, wherein the orthogonal transform circuit includes a discrete cosine transform (DCT) circuit.
Claim 51
Dependent Claim
50 words
The apparatus of claim 43, wherein the means for dividing the spectral components from the orthogonal transform circuit into critical bands divides spectral components in a frequency range of 0 Hz to 22 kHz into 25 critical bands having a bandwidth that broadens with increasing frequency of the critical band.
Claim 52
Dependent Claim
20 words
The apparatus of claim 45, wherein the critical bands in the block are at low frequencies in the frequency range.
Claim 53
Dependent Claim
72 words
The apparatus of claim 43, wherein: the adaptively-allocated number of bits used by the means for quantizing the spectral components in each critical band is indicated by a word length; and the apparatus additionally comprises a means for including in the compressed signal the floating coefficient for the block as the only floating coefficient for the critical bands in the block, and the work length for each critical band in the block.
Claim 54
Dependent Claim
84 words
The apparatus of claim 47, wherein the means for quantizing the spectral components in each critical band comprises means for: calculating a magnitude for each critical band from the spectral components in the critical band; calculating an allowed noise level for each critical band from the spectral components from the orthogonal transform circuit; and calculating the adaptively-allocated number of bits for each critical band from a level difference between the magnitude of the critical band and the allowed noise level of the critical band.
Claim 55
Dependent Claim
47 words
The apparatus of claim 47, wherein: the spectral components from the orthogonal transform circuit include amplitude information and phase information; and the means for calculating a magnitude for each critical band calculates the magnitude by summing the amplitude information of the spectral components in the critical band.
Claim 56
Dependent Claim
38 words
The apparatus of claim 49, wherein the means for quantizing the spectral components in each critical band includes a means for convoluting the magnitude of each critical band with a predetermined weighting function to take account of masking.
References Cited (Backward Citations)
US5117228A
Cited
US5134475A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1997-05-09 | 1997-11-08 | 1998-05-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-05-09 | 2001-11-08 | 2002-05-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-05-09 | 2005-11-08 | 2006-05-10 | $7700.00 | Window Closed / Lapsed |