US5673289A
Expired / Lapsed
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Method for encoding digital audio signals and apparatus thereof
Assignee: Samsung Electronics Co Ltd
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Filing: 1994-12-21
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Granted: 1997-09-30
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Expires: 2014-12-21
Abstract
Abstract A method and an apparatus for encoding a digital audio signal are provided. The method comprises the steps of: mapping the digital audio signal into a plurality of sub-bands and outputting the mapped sub-band signals; allocating a number of bits to each sub-band signal according to human psychoacoustic properties, on the basis of the mapped sub-band signals; compensating each sub-band signal by receiving a transmitted previous quantized error, quantizing the compensated sub-band signals according to the corresponding allocated bit number, and transferring the current quantized error to the next quantization; and forming a transmit bit stream in frame units from the quantized data. Therefore, the quantized error generated during encoding of the audio signal is can be minimized.
Inventors
- 👤 Sang-Wook Kim
- 👤 Yeon-bae Kim
- 👤 Yang-seock Seo
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 13:07
CPC Classifications
H; H04; H04B; H04B1/00; H04B1/66; H04B1/665; G; G11; G11B; G11B20/00
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
113 words
A method for encoding each digital audio signal of a plurality of channels comprising the steps of: mapping a digital audio signal into a plurality of sub-bands and outputting the mapped sub-band signals; allocating a number of bits to each mapped sub-band signal according to human psychoacoustic properties, on the basis of said mapped sub-band signals; compensating said each mapped sub-band signal by receiving a transmitted previous quantized error, quantizing the compensated sub-band signals according to the corresponding allocated bit number, and transferring the current quantized error to a next quantization of an adjacent frequency component of the same sub-band; and forming a transmit bit stream in frame units from said quantized data.
Claim 2
Independent Claim
113 words
A method for encoding each digital audio signal of a plurality of channels comprising the steps of: mapping a digital audio signal into a plurality of sub-bands and outputting the mapped sub-band signals; allocating a number of bits to each mapped sub-band signal according to human psychoacoustic properties, on the basis of said mapped sub-band signals; compensating said each mapped sub-band signal by receiving a transmitted previous quantized error, quantizing the compensated sub-band signals according to the corresponding allocated bit number, and transferring the current quantized error to a next quantization of an adjacent frequency component of the same sub-band; and forming a transmit bit stream in frame units from said quantized data.
Claim 3
Dependent Claim
24 words
A method for encoding a digital audio signal as claimed in claim 1, wherein said each sub-band is a critical band having undistinguishable tones.
Claim 4
Dependent Claim
136 words
A method for encoding a digital audio signal as claimed in claim 1, wherein said bit number allocating step comprises the steps of: calculating a signal-to-masked threshold ratio for each sub-band as a band ratio; calculating the sum of the band ratio of each sub-band to obtain each channel ratio of said plurality of channels; calculating an important factor of each channel according to the ratios of the respective channel ratio to sum of the channel ratios; allocating the channel bit number from total bit numbers according to said obtained important factor of each channel; calculating an important factor of each sub-band according to the ratios of the respective band ratios to said each channel ratio; and allocating the band bit number from said channel bit number according to said obtained important factor of each sub-band.
Claim 5
Dependent Claim
138 words
A method for encoding a digital audio signal as claimed in claim 3, wherein said masked threshold is obtained through the following steps of: discrete-Fourier-transforming an analog audio signal and calculating the quantity of each signal in every sub-band of said transformed signal; dividing the spectrum values in the sub-band of said transformed signal into a plurality of critical bands having undistinguishable tone and calculating the sum of power in each critical band; calculating the masked threshold by said undistinguishable tone signal frequency and said sum of power; setting up the maximum masked threshold in each critical band as a temporary masked threshold in the corresponding critical band; and comparing a no-signal threshold (absolute threshold) with said temporary masked threshold and setting up the higher of the two as a final masked threshold of the corresponding critical band.
Claim 6
Dependent Claim
42 words
A method for encoding a digital audio signal as claimed in claim 3, wherein said channel ratio of each channel is offset-corrected by subtracting a product value of the minimum band ratio among the band ratios multiplied by the number of bands.
Claim 7
Dependent Claim
43 words
A method for encoding a digital audio signal as claimed in claim 3, wherein said bit number of each band is allocated from a higher frequency component to a lower frequency component among said sub-band signals, considering the important factor of each band.
Claim 8
Dependent Claim
36 words
A method for encoding a digital audio signal as claimed in claim 3, wherein said ratio of each band is offset-corrected by subtracting the minimum band ratio of the ratios from the ratio of each band.
Claim 9
Dependent Claim
37 words
A method for encoding a digital audio signal as claimed in claim 3, wherein said important factor of the band is newly obtained from the ratio of the band to which a bit number is not allocated.
Claim 10
Dependent Claim
25 words
A method for encoding a digital audio signal as claimed in claim 3, wherein said bit number of a band is allocated considering band weight.
Claim 11
Dependent Claim
60 words
A method for encoding a digital audio signal as claimed in claim 1, comprising said quantizing step where the signals of each band are divided into tonal signals and non-tonal signals, the quantized error generated from a tonal signal is corrected by a tonal signal, and the quantized error generated from a non-tonal signal is corrected by a non-tonal signal.
Claim 12
Independent Claim
116 words
A method for encoding a digital audio signal comprising the steps of: mapping a digital audio signal into a plurality of sub-bands and outputting the mapped sub-band signals; allocating a number of bits to the mapped sub-band signal of each sub-band according to human psychoacoustic properties, on the basis of the mapped sub-band signals; compensating said each mapped sub-band signal by receiving a transmitted previous quantized error considering band weight, quantizing the compensated sub-band signal according to said allocated bit number, and transferring the current quantized error to a next quantization of an adjacent frequency component of the same sub-band considering band weight; and forming a transmit bit stream in frame units from said quantized data.
Claim 13
Independent Claim
116 words
A method for encoding a digital audio signal comprising the steps of: mapping a digital audio signal into a plurality of sub-bands and outputting the mapped sub-band signals; allocating a number of bits to the mapped sub-band signal of each sub-band according to human psychoacoustic properties, on the basis of the mapped sub-band signals; compensating said each mapped sub-band signal by receiving a transmitted previous quantized error considering band weight, quantizing the compensated sub-band signal according to said allocated bit number, and transferring the current quantized error to a next quantization of an adjacent frequency component of the same sub-band considering band weight; and forming a transmit bit stream in frame units from said quantized data.
Claim 14
Independent Claim
123 words
An apparatus for encoding a digital audio signal comprising: a mapping unit for mapping a digital audio signal into a plurality of sub-bands and outputting the mapped sub-band signals; a bit number allocating unit for allocating a number of bits to the sub-band signal of each band according to human psychoacoustic properties, on the basis of said mapped sub-band signals; a quantizing unit for compensating said each sub-band signal by receiving a transmitted previous quantized error, quantizing the compensated sub-band signal according to said allocated bit number, and transferring the current quantized error to a next quantization of an adjacent frequency component of the same sub-band; and frame packing means for forming a transmit bit stream in frame units from the quantized data.
Claim 15
Independent Claim
123 words
An apparatus for encoding a digital audio signal comprising: a mapping unit for mapping a digital audio signal into a plurality of sub-bands and outputting the mapped sub-band signals; a bit number allocating unit for allocating a number of bits to the sub-band signal of each band according to human psychoacoustic properties, on the basis of said mapped sub-band signals; a quantizing unit for compensating said each sub-band signal by receiving a transmitted previous quantized error, quantizing the compensated sub-band signal according to said allocated bit number, and transferring the current quantized error to a next quantization of an adjacent frequency component of the same sub-band; and frame packing means for forming a transmit bit stream in frame units from the quantized data.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2000-09-29 | 2001-03-31 | 2001-09-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-09-29 | 2005-03-31 | 2005-09-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-09-29 | 2009-03-31 | 2009-09-30 | $7700.00 | Window Closed / Lapsed |