公开(公告)号：US08260607B2

公开(公告)日：2012-09-04

申请号：US13076335

申请日：2011-03-30

Applicant: Lars Falck Villemoes ,  Per Ekstrand ,  Heiko Purnhagen ,  Erik Gosuinus Petrus Schuijers ,  Fransiscus Marinus Jozephus De Bont

Inventor： Lars Falck Villemoes ,  Per Ekstrand ,  Heiko Purnhagen ,  Erik Gosuinus Petrus Schuijers ,  Fransiscus Marinus Jozephus De Bont

IPC: G10L21/00 ,  G10L19/14 ,  G10L19/12 ,  G10L19/00

CPC classification number: G10L19/008 ,  G10L21/038

Abstract: Encoding an audio signal is provided wherein the audio signal includes a first audio channel and a second audio channel, the encoding comprising subband filtering each of the first audio channel and the second audio channel in a complex modulated filterbank to provide a first plurality of subband signals for the first audio channel and a second plurality of subband signals for the second audio channel, downsampling each of the subband signals to provide a first plurality of downsampled subband signals and a second plurality of downsampled subband signals, further subband filtering at least one of the downsampled subband signals in a further filterbank in order to provide a plurality of sub-subband signals, deriving spatial parameters from the sub-subband signals and from those downsampled subband signals that are not further subband filtered, and deriving a single channel audio signal comprising derived subband signals derived from the first plurality of downsampled subband signals and the second plurality of downsampled subband signals. Further, decoding is provided wherein an encoded audio signal comprising an encoded single channel audio signal and a set of spatial parameters is decoded by decoding the encoded single channel audio channel to obtain a plurality of downsampled subband signals, further subband filtering at least one of the downsampled subband signals in a further filterbank in order to provide a plurality of sub-subband signals, and deriving two audio channels from the spatial parameters, the sub-subband signals and those downsampled subband signals that are not further subband filtered.

Abstract translation: 提供对音频信号进行编码，其中音频信号包括第一音频通道和第二音频通道，该编码包括在复调制滤波器组中对第一音频通道和第二音频通道中的每一个进行子带滤波，以提供第一多个子带信号 对于第一音频通道和用于第二音频通道的第二多个子带信号，对每个子带信号进行下采样，以提供第一多个下采样子带信号和第二多个下采样子带信号，进一步的子带滤波至少一个 在另一个滤波器组中进行下采样的子带信号，以便提供多个子子带信号，从子子带信号和未被进一步子带滤波的那些下采样子带信号导出空间参数，以及导出包括导出的 从第一多个下采样子带信号导出的子带信号和 第二多个下采样子带信号。 此外，提供了解码，其中包括编码的单声道音频信号和一组空间参数的编码音频信号通过对编码的单声道音频声道进行解码以获得多个下采样的子带信号而被解码，进一步的子带滤波至少一个 在另一滤波器组中进行下采样的子带信号，以便提供多个子子带信号，以及从空间参数，子子带信号和未进一步子带滤波的那些下采样子带信号导出两个音频信道。

公开(公告)号：US20120195442A1

公开(公告)日：2012-08-02

申请号：US13499893

申请日：2010-05-20

Applicant: Lars Villemoes ,  Per Ekstrand

Inventor： Lars Villemoes ,  Per Ekstrand

IPC: H03G5/00

CPC classification number: C12Q1/6883 ,  C12Q2600/118 ,  C12Q2600/156 ,  G10L19/0204 ,  G10L19/022 ,  G10L19/265 ,  G10L21/038

Abstract: The present invention relates to coding of audio signals, and in particular to high frequency reconstruction methods including a frequency domain harmonic transposer. A system and method for generating a high frequency component of a signal from a low frequency component of the signal is described. The system comprises an analysis filter bank (501) comprising an analysis transformation unit (601) having a frequency resolution of Δf; and an analysis window (611) having a duration of DA; the analysis filter bank (501) being configured to provide a set of analysis subband signals from the low frequency component of the signal; a nonlinear processing unit (502, 650) configured to determine a set of synthesis subband signals based on a portion of the set of analysis subband signals, wherein the portion of the set of analysis subband signals is phase shifted by a transposition order T; and a synthesis filter bank (504) comprising a synthesis transformation unit (602) having a frequency resolution of QΔf; and a synthesis window (612) having a duration of Ds; the synthesis filter bank (504) being configured to generate the high frequency component of the signal from the set of synthesis subband signals; wherein Q is a frequency resolution factor with Q≧1 and smaller than the transposition order T; and wherein the value of the product of the frequency resolution Δf and the duration DA of the analysis filter bank is selected based on the frequency resolution factor Q.

Abstract translation: 本发明涉及音频信号的编码，特别涉及包括频域谐波转移器的高频重构方法。 描述了用于从信号的低频分量产生信号的高频分量的系统和方法。 该系统包括分析滤波器组（501），其包括频率分辨率为＆Dgr; f的分析变换单元（601） 和具有DA持续时间的分析窗口（611）; 所述分析滤波器组（501）被配置为从所述信号的低频分量提供一组分析子带信号; 非线性处理单元（502,650），被配置为基于所述一组分析子带信号来确定一组合成子带信号，其中所述一组分析子带信号的所述部分被相移一个换位阶数T; f）具有频率分辨率为Q＆Dgr; f的合成变换单元（602）的合成滤波器组（504） 和具有持续时间Ds的合成窗口（612）; 所述合成滤波器组（504）被配置为从所述一组合成子带信号中产生所述信号的高频分量; 其中Q是具有Q≥1且小于置换次数T的频率分辨率因子; 并且其中基于频率分辨率因子Q选择频率分辨率＆Dgr; f的乘积值和分析滤波器组的持续时间DA。

公开(公告)号：US20120029927A1

公开(公告)日：2012-02-02

申请号：US13230654

申请日：2011-09-12

Applicant: Lars G. LILJERYD ,  Kristofer Kjoerling ,  Per Ekstrand ,  Frederik Henn

Inventor： Lars G. LILJERYD ,  Kristofer Kjoerling ,  Per Ekstrand ,  Frederik Henn

IPC: H04B1/66

CPC classification number: G10L19/028 ,  G10L19/035 ,  G10L19/06 ,  G10L19/26 ,  G10L19/265 ,  G10L21/038 ,  G10L25/18

Abstract: Methods and an apparatus for enhancement of source coding systems utilizing high frequency reconstruction (HFR) are introduced. The problem of insufficient noise contents is addressed in a reconstructed highband, by using Adaptive Noise-floor Addition. New methods are also introduced for enhanced performance by means of limiting unwanted noise, interpolation and smoothing of envelope adjustment amplification factors. The methods and apparatus used are applicable to both speech coding and natural audio coding systems.

Abstract translation: 引入了利用高频重建（HFR）来增强源编码系统的方法和装置。 通过使用自适应噪声层加法，在重构的高频带中解决噪声含量不足的问题。 还引入了新的方法，通过限制不需要的噪声，包络调整放大因子的内插和平滑来增强性能。 所使用的方法和装置适用于语音编码和自然音频编码系统。

公开(公告)号：US20110274281A1

公开(公告)日：2011-11-10

申请号：US13145758

申请日：2010-01-13

Applicant: C. Phillip Brown ,  Per Ekstrand ,  Alan Seefeldt

Inventor： C. Phillip Brown ,  Per Ekstrand ,  Alan Seefeldt

IPC: H04R29/00

CPC classification number: H04R29/001 ,  H04R3/04 ,  H04R2430/03

Abstract: A method for determining an inverse filter for altering the frequency response of a loudspeaker so that with the inverse filter applied in the loudspeaker's signal path the inverse-filtered loudspeaker output has a target frequency response, and optionally also applying the inverse filter in the signal path, and a system configured (e.g., a general or special purpose processor programmed and configured) to determine an inverse filter. In some embodiments, the inverse filter corrects the magnitude of the loudspeaker's output. In other embodiments, the inverse filter corrects both the magnitude and phase of the loudspeaker's output. In some embodiments, the inverse filter is determined in the frequency domain by applying eigenfilter theory or minimizing a mean square error expression by solving a linear equation system.

Abstract translation: 一种用于确定用于改变扬声器的频率响应的逆滤波器的方法，使得利用在扬声器信号路径中应用的反相滤波器，经滤波的扬声器输出具有目标频率响应，并且还可选地还在信号路径中应用逆滤波器 以及配置（例如，编程和配置的通用或专用处理器）以确定逆滤波器的系统。 在一些实施例中，逆滤波器校正扬声器输出的幅度。 在其他实施例中，逆滤波器校正扬声器的输出的幅度和相位。 在一些实施例中，通过应用特征滤波器理论或通过求解线性方程系统来最小化均方误差表达式，在频域中确定逆滤波器。

公开(公告)号：US07917561B2

公开(公告)日：2011-03-29

申请号：US11463263

申请日：2006-08-08

Applicant: Per Ekstrand ,  Lars Villemoes ,  Heiko Purnhagen

Inventor： Per Ekstrand ,  Lars Villemoes ,  Heiko Purnhagen

IPC: G06F17/10

CPC classification number: G10L19/0208

Abstract: An apparatus for processing a plurality of real-valued subband signals using a first real-valued subband signal and a second real-valued subband signal to provide at least a complex-valued subband signal comprises a multiband filter for providing an intermediate real-valued subband signal and a calculator for providing the complex-valued subband signal by combining a real-valued subband signal from the plurality of real-valued subband signals and the intermediate subband signal.

Abstract translation: 一种用于使用第一实值子带信号和第二实值子带信号来处理多个实值子带信号以提供至少复值子带信号的装置包括多频带滤波器，用于提供中间实值子带 信号和用于通过组合来自多个实值子带信号和中间子带信号的实值子带信号来提供复值子带信号的计算器。

公开(公告)号：US07680552B2

公开(公告)日：2010-03-16

申请号：US12253135

申请日：2008-10-16

Applicant: Lars Liljeryd ,  Per Ekstrand ,  Fredrik Henn ,  Kristofer Kjoerling

Inventor： Lars Liljeryd ,  Per Ekstrand ,  Fredrik Henn ,  Kristofer Kjoerling

IPC: G06F17/00

CPC classification number: G10L19/0208 ,  G10L19/0017 ,  G10L19/0204 ,  G10L19/26 ,  G10L19/265 ,  G10L21/038

Abstract: The present invention relates to a new method and apparatus for improvement of High Frequency Reconstruction (HFR) techniques using frequency translation or folding or a combination thereof. The proposed invention is applicable to audio source coding systems, and offers significantly reduced computational complexity. This is accomplished by means of frequency translation or folding in the subband domain, preferably integrated with spectral envelope adjustment in the same domain. The concept of dissonance guard-band filtering is further presented. The proposed invention offers a low-complexity, intermediate quality HFR method useful in speech and natural audio coding applications.

Abstract translation: 本发明涉及使用频率转换或折叠或其组合来改进高频重建（HFR）技术的新方法和装置。 所提出的发明适用于音频源编码系统，并提供显着降低的计算复杂度。 这通过在子带域中的频率转换或折叠来实现，优选地与同一域中的频谱包络调整集成。 进一步提出了不一致保卫带滤波的概念。 所提出的发明提供了一种在语音和自然音频编码应用中有用的低复杂度，中等质量的HFR方法。

公开(公告)号：US20090315748A1

公开(公告)日：2009-12-24

申请号：US12490990

申请日：2009-06-24

Applicant: Lars G. Liljeryd ,  Kristofer Kjoerling ,  Per Ekstrand ,  Fredrik Henn

Inventor： Lars G. Liljeryd ,  Kristofer Kjoerling ,  Per Ekstrand ,  Fredrik Henn

IPC: H03M1/66

CPC classification number: G10L19/028 ,  G10L19/035 ,  G10L19/06 ,  G10L19/26 ,  G10L19/265 ,  G10L21/038 ,  G10L25/18

Abstract: Methods and an apparatus for enhancement of source coding systems utilizing high frequency reconstruction (HFR) are introduced. The problem of insufficient noise contents is addressed in a reconstructed highband, by using Adaptive Noise-floor Addition. New methods are also introduced for enhanced performance by means of limiting unwanted noise, interpolation and smoothing of envelope adjustment amplification factors. The methods and apparatus used are applicable to both speech coding and natural audio coding systems.

公开(公告)号：US07519538B2

公开(公告)日：2009-04-14

申请号：US10577106

申请日：2004-10-28

Applicant: Lars Falck Villemoes ,  Per Ekstrand ,  Heiko Purnhagen ,  Erik Gosuinus Petrus Schuijers ,  Fransiscus Marinus Jozephus de Bont

Inventor： Lars Falck Villemoes ,  Per Ekstrand ,  Heiko Purnhagen ,  Erik Gosuinus Petrus Schuijers ,  Fransiscus Marinus Jozephus de Bont

IPC: G10L19/00 ,  G10L19/14

CPC classification number: G10L19/008 ,  G10L21/038

Abstract: Encoding an audio signal is provided wherein the audio signal includes a first audio channel and a second audio channel, the encoding comprising subband filtering each of the first audio channel and the second audio channel in a complex modulated filterbank to provide a first plurality of subband signals for the first audio channel and a second plurality of subband signals for the second audio channel, downsampling each of the subband signals to provide a first plurality of downsampled subband signals and a second plurality of downsampled subband signals, further subband filtering at least one of the downsampled subband signals in a further filterbank in order to provide a plurality of sub-subband signals, deriving spatial parameters from the sub-subband signals and from those downsampled subband signals that are not further subband filtered, and deriving a single channel audio signal comprising derived subband signals derived from the first plurality of downsampled subband signals and the second plurality of downsampled subband signals. Further, decoding is provided wherein an encoded audio signal comprising an encoded single channel audio signal and a set of spatial parameters is decoded by decoding the encoded single channel audio channel to obtain a plurality of downsampled subband signals, further subband filtering at least one of the downsampled subband signals in a further filterbank in order to provide a plurality of sub-subband signals, and deriving two audio channels from the spatial parameters, the sub-subband signals and those downsampled subband signals that are not further subband filtered.

Abstract translation: 提供对音频信号进行编码，其中音频信号包括第一音频通道和第二音频通道，该编码包括在复调制滤波器组中对第一音频通道和第二音频通道中的每一个进行子带滤波，以提供第一多个子带信号 对于第一音频通道和用于第二音频通道的第二多个子带信号，对每个子带信号进行下采样以提供第一多个下采样子带信号和第二多个下采样子带信号，进一步子带滤波至少一个 在另一个滤波器组中进行下采样的子带信号，以便提供多个子子带信号，从子子带信号和未进一步子带滤波的那些下采样子带信号导出空间参数，以及导出包括导出的 从第一多个下采样子带信号导出的子带信号和 第二多个下采样子带信号。 此外，提供了解码，其中包括编码的单声道音频信号和一组空间参数的编码音频信号通过对编码的单声道音频声道进行解码以获得多个下采样的子带信号而被解码，进一步的子带滤波至少一个 在另一滤波器组中进行下采样的子带信号，以便提供多个子子带信号，以及从空间参数，子子带信号和未进一步子带滤波的那些下采样子带信号导出两个音频信道。

公开(公告)号：US20070067162A1

公开(公告)日：2007-03-22

申请号：US10577106

申请日：2004-10-28

Applicant: Lars Villemoes ,  Per Ekstrand ,  Heiko Purnhagen ,  Erik Schuijers ,  Fransiscus de Bont

Inventor： Lars Villemoes ,  Per Ekstrand ,  Heiko Purnhagen ,  Erik Schuijers ,  Fransiscus de Bont

IPC: G10L11/04

CPC classification number: G10L19/008 ,  G10L21/038

Abstract: Encoding an audio signal is provided wherein the audio signal includes a first audio channel and a second audio channel, the encoding comprising subband filtering each of the first audio channel and the second audio channel in a complex modulated filterbank to provide a first plurality of subband signals for the first audio channel and a second plurality of subband signals for the second audio channel, downsampling each of the subband signals to provide a first plurality of downsampled subband signals and a second plurality of downsampled subband signals, further subband filtering at least one of the downsampled subband signals in a further filterbank in order to provide a plurality of sub-subband signals, deriving spatial parameters from the sub-subband signals and from those downsampled subband signals that are not further subband filtered, and deriving a single channel audio signal comprising derived subband signals derived from the first plurality of downsampled subband signals and the second plurality of downsampled subband signals. Further, decoding is provided wherein an encoded audio signal comprising an encoded single channel audio signal and a set of spatial parameters is decoded by decoding the encoded single channel audio channel to obtain a plurality of downsampled subband signals, further subband filtering at least one of the downsampled subband signals in a further filterbank in order to provide a plurality of sub-subband signals, and deriving two audio channels from the spatial parameters, the sub-subband signals and those downsampled subband signals that are not further subband filtered.

Abstract translation: 提供对音频信号进行编码，其中音频信号包括第一音频通道和第二音频通道，该编码包括在复调制滤波器组中对第一音频通道和第二音频通道中的每一个进行子带滤波，以提供第一多个子带信号 对于第一音频通道和用于第二音频通道的第二多个子带信号，对每个子带信号进行下采样以提供第一多个下采样子带信号和第二多个下采样子带信号，进一步子带滤波至少一个 在另一个滤波器组中进行下采样的子带信号，以便提供多个子子带信号，从子子带信号和未进一步子带滤波的那些下采样子带信号导出空间参数，以及导出包括导出的 从第一多个下采样子带信号导出的子带信号和 第二多个下采样子带信号。 此外，提供了解码，其中包括编码的单声道音频信号和一组空间参数的编码音频信号通过对编码的单声道音频声道进行解码以获得多个下采样的子带信号而被解码，进一步的子带滤波至少一个 在另一滤波器组中进行下采样的子带信号，以便提供多个子子带信号，以及从空间参数，子子带信号和未进一步子带滤波的那些下采样子带信号导出两个音频信道。

公开(公告)号：US06978236B1

公开(公告)日：2005-12-20

申请号：US09763128

申请日：2000-01-26

Applicant: Lars Gustaf Liljeryd ,  Kristofer Kjorling ,  Per Ekstrand ,  Fredrik Henn

Inventor： Lars Gustaf Liljeryd ,  Kristofer Kjorling ,  Per Ekstrand ,  Fredrik Henn

IPC: G10L20060101 ,  G10L19/02 ,  G10L19/022 ,  G10L19/035 ,  G10L19/06 ,  G10L21/02 ,  G10L21/038 ,  G10L25/18 ,  G10L19/00

CPC classification number: G10L19/06 ,  G10L19/0208 ,  G10L19/022 ,  G10L19/035 ,  G10L21/038 ,  G10L25/18

Abstract: The present invention provides a new method and an apparatus for spectral envelope encoding. The invention teaches how to perform and signal compactly a time/frequency mapping of the envelope representation, and further, encode the spectral envelope data efficiently using adaptive time/frequency directional coding. The method is applicable to both natural audio coding and speech coding systems and is especially suited for coders using SBR [WO 98/57436] or other high frequency reconstruction methods.

Abstract translation: 本发明提供了一种用于频谱包络编码的新方法和装置。 本发明教导了如何执行和紧凑地发送包络表示的时间/频率映射，并且还使用自适应时间/频率方向编码有效地对频谱包络数据进行编码。 该方法适用于自然音频编码和语音编码系统，并且特别适用于使用SBR [WO 98/57436]或其他高频重建方法的编码器。