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公开(公告)号：US20180182403A1
公开(公告)日：2018-06-28
申请号：US15809623
申请日：2017-11-10
申请人： FUJITSU LIMITED
发明人： Akira Kamano , Yohei KISHI , Masanao SUZUKI
CPC分类号： G10L19/0208 , G10L19/0204 , G10L19/24 , G10L19/26 , G10L21/0216 , G10L21/038 , G10L25/18
摘要： An audio coding device includes a filter configured to extract a low-band signal having a first frequency component from an input signal, a memory, and a processor coupled to the memory and configured to extract envelope information relating to an envelope of a high-band signal having a second frequency component which is higher than the first frequency component in the input signal, detect tone information that is information on a tone signal included in a high-band signal spectrum from the input signal, correct the envelope information based on a difference between frequency of the tone signal and frequency of a peak of the envelope, and code the low-band signal, the tone information, and the envelope information that is corrected.
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132.发明授权公开(公告)号：US09990929B2
公开(公告)日：2018-06-05
申请号：US15799641
申请日：2017-10-31
CPC分类号： G10L19/0204 , G10L19/00 , G10L19/025 , G10L19/083 , G10L19/12 , G10L19/26 , G10L25/12 , G10L25/18 , G10L25/21 , G10L25/48 , H03H17/0266
摘要： The present invention proposes a new method for improving the performance of a real-valued filterbank based spectral envelope adjuster. By adaptively locking the gain values for adjacent channels dependent on the sign of the channels, as defined in the application, reduced aliasing is achieved. Furthermore, the grouping of the channels during gain-calculation, gives an improved energy estimate of the real valued subband signals in the filterbank.
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公开(公告)号：US09984699B2
公开(公告)日：2018-05-29
申请号：US14750784
申请日：2015-06-25
IPC分类号： G10L19/26 , G10L19/04 , G10L21/038
CPC分类号： G10L19/265 , G10L19/04 , G10L21/038
摘要： A method includes generating a first signal corresponding to a first component of a high-band portion of an audio signal. The first component has a first frequency range. The method includes generating a high-band excitation signal corresponding to a second component of the high-band portion of the audio signal. The second component has a second frequency range differs from the first frequency range. The high-band excitation signal is provided to a filter having filter coefficients generated based on the first signal to generate a synthesized version of the high-band portion of the audio signal.
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公开(公告)号：US09978385B2
公开(公告)日：2018-05-22
申请号：US15031130
申请日：2014-10-21
IPC分类号： G10L19/008 , G10L19/16 , G10L19/26 , H04S5/00
CPC分类号： G10L19/167 , G10L19/008 , G10L19/265 , H04S5/005 , H04S2420/03
摘要： An encoding system (400) encodes an N-channel audio signal (X), wherein N≥3, as a single-channel downmix signal (Y) together with dry and wet upmix parameters (C, P). In a decoding system (200), a decorrelating section (101) outputs, based on the downmix signal, an (N−1)-channel decorrelated signal (Z); a dry upmix section (102) maps the downmix signal linearly in accordance with dry upmix coefficients (C) determined based on the dry upmix parameters; a wet upmix section (103) populates an intermediate matrix based on the wet upmix parameters and knowing that the intermediate matrix belongs to a predefined matrix class, obtains wet upmix coefficients (P) by multiplying the intermediate matrix by a predefined matrix, and maps the decorrelated signal linearly in accordance with the wet upmix coefficients; and a combining section (104) combines outputs from the upmix sections to obtain a reconstructed signal (X) corresponding to the signal to be reconstructed.
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公开(公告)号：US20180102133A1
公开(公告)日：2018-04-12
申请号：US15683325
申请日：2017-08-22
IPC分类号： G10L19/26 , H03G9/14 , H03G5/00 , H03G9/00 , H03G9/02 , H03G3/00 , G10L21/034 , G10L21/0388 , H03G5/16
CPC分类号： G10L19/26 , G10L21/034 , G10L21/0388 , H03G3/00 , H03G5/005 , H03G5/165 , H03G9/005 , H03G9/025 , H03G9/14
摘要： The present invention provides methods and systems for narrow bandwidth digital processing of an input audio signal. Particularly, the present invention includes a high pass filter configured to filter the input audio signal. A first compressor then modulates the filtered signal in order to create a partially processed signal. In some embodiments, a clipping module further limits the gain of the partially processed signal. A splitter is configured to split the partially processed signal into a first signal and a second signal. A low pass filter is configured to filter the first signal. A pass through module is configured to adjust the gain of the second signal. A mixer then combines the filtered first signal and the gain-adjusted second signal in order to output a combined signal. In some embodiments, a tone control module further processes the combined signal, and a second compressor further modulates the processed signal.
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公开(公告)号：US09940941B2
公开(公告)日：2018-04-10
申请号：US15480859
申请日：2017-04-06
发明人： Lars Villemoes
IPC分类号： G10L19/02 , G10L19/025 , G10L19/26
CPC分类号： G10L19/0208 , G10L19/025 , G10L19/265 , G10L21/038 , G10L21/04 , H03G3/00 , H03G3/3089
摘要： The invention provides an efficient implementation of cross-product enhanced high-frequency reconstruction (HFR), wherein a new component at frequency QΩ+rΩ0 is generated on the basis of existing components at Ω and Ω+Ω0. The invention provides a block-based harmonic transposition, wherein a time block of complex subband samples is processed with a common phase modification. Superposition of several modified samples has the net effect of limiting undesirable intermodulation products, thereby enabling a coarser frequency resolution and/or lower degree of oversampling to be used. In one embodiment, the invention further includes a window function suitable for use with block-based cross-product enhanced HFR. A hardware embodiment of the invention may include an analysis filter bank, a subband processing unit configurable by control data and a synthesis filter bank.
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公开(公告)号：US09928852B2
公开(公告)日：2018-03-27
申请号：US14965528
申请日：2015-12-10
申请人： Orange
发明人： Arnault Nagle , Claude Lamblin
摘要： A method is provided for detecting a predetermined frequency band in an audio data signal which has previously been coded according to a succession of data blocks, among which at least certain blocks contain respectively at least one set of spectral parameters representing a linear prediction filter. Such a method of detection implements, for a current block among the at least certain blocks and for which at least a plurality of spectral parameters of the set have been previously decoded, acts of: determining, among the plurality of previously decoded spectral parameters, the index of the first spectral parameter closest to a threshold frequency; calculating at least one criterion on the basis of the determined index; and deciding whether the predetermined frequency band is detected in the current block, as a function of the criterion calculated.
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公开(公告)号：US09905236B2
公开(公告)日：2018-02-27
申请号：US14384350
申请日：2013-03-21
摘要： An audio communication endpoint receives a bitstream containing spectral components representing spectral content of an audio signal, wherein the spectral components relate to a first range extending up to a first break frequency, above which any spectral components are unassigned. The endpoint adapts the received bitstream in accordance with a second range extending up to a second break frequency by removing spectral components or adding neutral-valued spectral components relating to a range between the first and second break frequencies. The endpoint then attenuates spectral content in a neighborhood of the least of the first and second break frequencies for thereby achieving a gradual spectral decay. After this, reconstructing the audio signal is reconstructed by an inverse transform operating on spectral components relating to said second range in the adapted and attenuated received bitstream. At small computational expense, the endpoint may to adapt to different sample rates in received bitstreams.
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公开(公告)号：US09892741B2
公开(公告)日：2018-02-13
申请号：US15486943
申请日：2017-04-13
发明人： Lars Villemoes
IPC分类号： G10L19/00 , G10L19/02 , G10L19/06 , G10L19/26 , G10L19/005 , G10L19/032
CPC分类号： G10L19/0208 , G06F17/5045 , G06F17/505 , G10L19/005 , G10L19/0212 , G10L19/032 , G10L19/06 , G10L19/093 , G10L19/26 , G10L19/265
摘要： The present document relates to audio source coding systems. In particular, the present document relates to audio source coding systems which make use of linear prediction in combination with a filterbank. A method for estimating a first sample (615) of a first subband signal in a first subband of an audio signal is described. The first subband signal of the audio signal is determined using an analysis filterbank (612) comprising a plurality of analysis filters which provide a plurality of subband signals in a plurality of subbands from the audio signal, respectively. The method comprises determining a model parameter (613) of a signal model; determining a prediction coefficient to be applied to a previous sample (614) of a first decoded subband signals derived from the first subband signal, based on the signal model, based on the model parameter (613) and based on the analysis filterbank (612); wherein a time slot of the previous sample (614) is prior to a time slot of the first sample (615); and determining an estimate of the first sample (615) by applying the prediction coefficient to the previous sample (614).
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公开(公告)号：US09886964B2
公开(公告)日：2018-02-06
申请号：US15646645
申请日：2017-07-11
IPC分类号： G10L21/0388 , G10L19/26 , G10L19/02
CPC分类号： G10L19/265 , G10L19/0204 , G10L21/0388
摘要： A coding apparatus encodes a first band of an input audio signal, normalizes a first spectrum included in each sub-band of the first band using a spectrum power envelope, performs a clipping process on the normalized first spectrum, the clipping process comparing between a predetermined threshold and the absolute value of an amplitude of the spectrum and replaces the amplitude value of the spectrum with the threshold if the absolute value of the amplitude of the spectrum exceeds the threshold, calculates a correlation between a spectrum in each divided band of a second band and a spectrum in a plurality of candidate bands containing the clipped normalized first spectrum, the second spectrum being higher than a predetermined frequency, identifies the best bands of the plurality of candidate bands, and encodes the second spectrum using lag information identifying the best band for transmitting the lag information to a decoder.
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