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1.发明公开EFFICIENT SPECTRAL ENVELOPE CODING USING VARIABLE TIME/FREQUENCY RESOLUTION AND TIME/FREQUENCY SWITCHING 有权使用可变时间/频率分辨率和时间/频率切换的有效谱包络编码
公开(公告)号：EP1216474A1
公开(公告)日：2002-06-26
申请号：EP00968271.7
申请日：2000-09-29
IPC分类号： G10L19/00
CPC分类号： G10L19/06 , G10L19/0208 , G10L19/022 , G10L19/035 , G10L21/038 , G10L25/18
摘要： 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.
摘要翻译： 本发明提供了一种用于频谱包络编码的新方法和装置。 本发明教导如何紧凑地执行和发送包络表示的时间/频率映射，并进一步使用自适应时间/频率定向编码有效地编码频谱包络数据。 该方法适用于自然音频编码和语音编码系统，特别适用于使用SBR [WO 98/57436]或其他高频重建方法的编码器。
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2.发明公开ENHANCING PERCEPTUAL PERFORMANCE OF SBR AND RELATED HFR CODING METHODS BY ADAPTIVE NOISE-FLOOR ADDITION AND NOISE SUBSTITUTION LIMITING 有权主观SBR（谱带复制）及HFR（高频重建）质量的提高编码BY添加杂色从地面和限制噪声替代
公开(公告)号：EP1157374A2
公开(公告)日：2001-11-28
申请号：EP00904174.0
申请日：2000-01-26
IPC分类号： G10L19/00
CPC分类号： G10L19/028 , G10L19/035 , G10L19/06 , G10L19/26 , G10L19/265 , G10L21/038 , G10L25/18
摘要： The present proposes new methods and an apparatus for enhancement of source coding systems utilising high frequency reconstruction (HFR). It addresses the problem of insufficient noise contents in a reconstructed highband, by Adaptive Noise-floor Addition. It also introduces new methods for enhanced performance by means of limiting unwanted noise, interpolation and smoothing of envelope adjustment amplification factors. The present invention is applicable to both speech coding and natural audio coding systems.
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公开(公告)号：EP1374399A1
公开(公告)日：2004-01-02
申请号：EP02718740.0
申请日：2002-03-28
发明人： EKSTRAND, Per
IPC分类号： H03H17/00
CPC分类号： H03H17/0266
摘要： The present invention proposes a new method and apparatus for the improvement of digital filterbanks, by a complex extension of cosine modulated digital filterbanks. The invention employs complex-exponential modulation of a low-pass prototype filter and a new method for optimizing the characteristics of this filter. The invention substantially reduces artifacts due to aliasing emerging from independent modifications of subband signals, for example when using a filterbank as an spectral equalizer. The invention is preferably implemented in software, running on a standard PC or a digital signal processor (DSP), but can also be hardcoded on a custom chip. The invention offers essential improvements for various types of digital equalizers, adaptive filters, multiband companders and spectral envelope adjusting filterbanks used in high frequency reconstruction (HFR) systems.
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4.发明公开ENHANCING PERCEPTUAL PERFORMANCE OF HIGH FREQUENCY RECONSTRUCTION CODING METHODS BY ADAPTIVE FILTERING 有权IMPROVE高频重建编码方法通过自适应滤波知觉相关的性能
公开(公告)号：EP1342230A1
公开(公告)日：2003-09-10
申请号：EP01983041.3
申请日：2001-11-13
CPC分类号： G10L21/038
摘要： The present invention proposes a new method and a new apparatus for enhancement of audio source coding systems utilising high frequency reconstruction (HFR). It utilises adaptive filtering to reduce artifacts due to different tonal characteristics in different frequency ranges of an audio signal upon which HFR is performed. The present invention is applicable to both speech coding and natural audio coding systems.
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公开(公告)号：EP1285436A1
公开(公告)日：2003-02-26
申请号：EP01937069.1
申请日：2001-05-23
IPC分类号： G10L19/00
CPC分类号： G10L19/0208 , G10L19/0017 , G10L19/0204 , G10L19/26 , G10L19/265 , G10L21/038
摘要： The method involves filtering a low band signal through the analysis part of a digital filter bank and obtaining a set of subband signals. A number of the subband signals are patched from consecutive channels of the filter bank to consecutive channels in the synthesis part of a digital filter bank. Each of the subband signals is patched from a channel with frequency index k to a channel with frequency index j not equal to k. The patched subband signals are adjusted in accordance to a desired spectral envelope. The adjusted subband signals are filtered through the synthesis part of a digital filter bank. An envelope adjusted and frequency translated or folded signal is obtained. An Independent claim is included for an apparatus for enhancement of source coding systems using high-frequency reconstruction techniques.
摘要翻译： 本发明涉及用于改进使用频率转换或折叠或其组合的高频重建（HFR）技术的新方法和设备。 所提出的发明适用于音频源编码系统，并且提供显着降低的计算复杂度。 这通过子频带域中的频率变换或折叠来完成，优选地与相同域中的频谱包络调整相结合。 进一步介绍了不谐调保护带滤波的概念。 所提出的发明提供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。
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公开(公告)号：EP1285436B1
公开(公告)日：2003-09-17
申请号：EP01937069.1
申请日：2001-05-23
IPC分类号： G10L21/02
CPC分类号： G10L19/0208 , G10L19/0017 , G10L19/0204 , G10L19/26 , G10L19/265 , G10L21/038
摘要： The method involves filtering a low band signal through the analysis part of a digital filter bank and obtaining a set of subband signals. A number of the subband signals are patched from consecutive channels of the filter bank to consecutive channels in the synthesis part of a digital filter bank. Each of the subband signals is patched from a channel with frequency index k to a channel with frequency index j not equal to k. The patched subband signals are adjusted in accordance to a desired spectral envelope. The adjusted subband signals are filtered through the synthesis part of a digital filter bank. An envelope adjusted and frequency translated or folded signal is obtained. An Independent claim is included for an apparatus for enhancement of source coding systems using high-frequency reconstruction techniques.
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公开(公告)号：EP1338000A1
公开(公告)日：2003-08-27
申请号：EP01272413.4
申请日：2001-12-19
IPC分类号： G10L19/00
CPC分类号： G10L21/038
摘要： The present invention relates to a new method for enhancement of source coding systems using high-frequency reconstruction. The invention teaches that tonal signals can be classified as either pulse-train-like or non-pulse-train-like. Relying on this classification, significant improvements on the perceived audio quality can be obtained by adaptive switching of transposers. The invention shows that the so-switched transposers must have fundamental differences in their characteristics.
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