Method and apparatus for using coding scheme selection patterns in a predictive speech coder to reduce sensitivity to frame error conditions
    4.
    发明授权
    Method and apparatus for using coding scheme selection patterns in a predictive speech coder to reduce sensitivity to frame error conditions 有权
    在预测语音编码器中使用编码方案选择模式以降低对帧错误状况的灵敏度的方法和装置

    公开(公告)号:US06438518B1

    公开(公告)日:2002-08-20

    申请号:US09429754

    申请日:1999-10-28

    IPC分类号: G10L1904

    CPC分类号: G10L19/18 G10L19/02

    摘要: A method and apparatus for using coding scheme selection patterns in a predictive speech coder to reduce sensitivity to frame error conditions includes a speech coder configured to select from among various predictive coding modes. After a predefined number of speech frames have been predictively coded, the speech coder codes one frame with a nonpredictive coding mode or a mildly predictive coding mode. The predefined number of frames can be determined in advance from the subjective standpoint of a listener. The predefined number of frames may be varied periodically. An average coding bit rate may be maintained for the speech coder by ensuring that an average coding bit rate is maintained for each successive pattern, or group, of predictively coded speech frames including at least one nonpredictively coded or mildly predictively coded speech frame.

    摘要翻译: 一种用于在预测语音编码器中使用编码方案选择模式以降低对帧错误状况的灵敏度的方法和装置包括配置成从各种预测编码模式中进行选择的语音编码器。 在预定数量的语音帧已被预测编码之后,语音编码器以非预测编码模式或轻度预测编码模式对一帧进行编码。 可以从收听者的主观角度预先确定预定数量的帧。 预定数量的帧可以周期性地改变。 可以通过确保针对包括至少一个非预测编码或温和预测编码的语音帧的预测编码语音帧的每个连续模式或组维持平均编码比特率来维持语音编码器的平均编码比特率。

    Frame erasure compensation method in a variable rate speech coder
    5.
    发明授权
    Frame erasure compensation method in a variable rate speech coder 有权
    可变速率语音编码器中的帧擦除补偿方法

    公开(公告)号:US06584438B1

    公开(公告)日:2003-06-24

    申请号:US09557283

    申请日:2000-04-24

    IPC分类号: G10L1300

    摘要: A frame erasure compensation method in a variable-rate speech coder includes quantizing, with a first encoder, a pitch lag value for a current frame and a first delta pitch lag value equal to the difference between the pitch lag value for the current frame and the pitch lag value for the previous frame. A second, predictive encoder quantizes only a second delta pitch lag value for the previous frame (equal to the difference between the pitch lag value for the previous frame and the pitch lag value for the frame prior to that frame). If the frame prior to the previous frame is processed as a frame erasure, the pitch lag value for the previous frame is obtained by subtracting the first delta pitch lag value from the pitch lag value for the current frame. The pitch lag value for the erasure frame is then obtained by subtracting the second delta pitch lag value from the pitch lag value for the previous frame. Additionally, a waveform interpolation method may be used to smooth discontinuities caused by changes in the coder pitch memory.

    摘要翻译: 可变速率语音编码器中的帧擦除补偿方法包括:利用第一编码器量化当前帧的音调滞后值,以及等于当前帧的音调滞后值与第 前一帧的音调滞后值。 第二预测编码器仅量化前一帧的第二增量音调滞后值(等于先前帧的音调滞后值与该帧之前的帧的音调滞后值之间的差)。 如果先前帧之前的帧被作为帧擦除处理,则通过从当前帧的音调滞后值中减去第一增量音调滞后值来获得先前帧的音调滞后值。 然后通过从前一帧的音调滞后值减去第二增量音调滞后值来获得擦除帧的音调滞后值。 此外,可以使用波形插值方法来平滑由编码器音调存储器的变化引起的不连续性。

    Amplitude quantization scheme for low-bit-rate speech coders
    6.
    发明授权
    Amplitude quantization scheme for low-bit-rate speech coders 有权
    低比特率语音编码器的幅度量化方案

    公开(公告)号:US06324505B1

    公开(公告)日:2001-11-27

    申请号:US09356756

    申请日:1999-07-19

    IPC分类号: G10L2102

    CPC分类号: G10L19/0204 G10L25/18

    摘要: An amplitude quantization scheme for low-bit-rate speech coders includes the first step of extracting a vector of spectral information from a frame. The energy of the vector is normalized to generate gain factors. The gain factors are differentially vector quantized. The normalized gain factors are non-uniformly downsampled to generate a fixed-dimension vector with elements associated with a set of non-uniform frequency bands. The fixed-dimension vector is split into two or more sub-vectors. The sub-vectors are differentially quantized, to best advantage with a harmonic cloning process.

    摘要翻译: 用于低比特率语音编码器的幅度量化方案包括从帧提取频谱信息的向量的第一步骤。 向量的能量被归一化以产生增益因子。 增益因子是差分矢量量化的。 归一化的增益因子被非均匀地下采样以产生具有与一组非均匀频带相关联的元素的固定维度向量。 固定维度向量被分成两个或多个子向量。 子矢量被差分量化,以利用谐波克隆过程的最佳优势。

    Method and apparatus for interleaving line spectral information quantization methods in a speech coder
    7.
    发明授权
    Method and apparatus for interleaving line spectral information quantization methods in a speech coder 有权
    用于在语音编码器中交织线谱信息量化方法的方法和装置

    公开(公告)号:US06393394B1

    公开(公告)日:2002-05-21

    申请号:US09356755

    申请日:1999-07-19

    IPC分类号: G10L2100

    摘要: A method and apparatus for interleaving line spectral information quantization methods in a speech coder includes quantizing line spectral information with two vector quantization techniques, the first technique being a non-moving-average prediction-based technique, and the second technique being a moving-average prediction-based technique. A line spectral information vector is vector quantized with the first technique. Equivalent moving average codevectors for the first technique are computed. A memory of a moving average codebook of codevectors is updated with the equivalent moving average codevectors for a predefined number of frames that were previously processed by the speech coder. A target quantization vector for the second technique is calculated based on the updated moving average codebook memory. The target quantization vector is vector quantized with the second technique to generate a quantized target codevector. The memory of the moving average codebook is updated with the quantized target codevector. Quantized line spectral information vectors are derived from the quantized target codevector.

    摘要翻译: 用于在语音编码器中交织线谱信息量化方法的方法和装置包括使用两个矢量量化技术量化线谱信息,第一技术是基于非移动平均预测的技术,第二技术是移动平均 基于预测的技术。 线谱信息矢量用第一技术进行矢量量化。 计算第一种技术的等效移动平均码矢量。 代码矢量的移动平均码本的存储器用先前由语音编码器处理的预定数量的帧的等效移动平均码向量更新。 基于更新的移动平均码本存储器计算第二技术的目标量化矢量。 目标量化矢量用第二技术进行矢量量化,以产生量化的目标码矢量。 用量化的目标码矢量来更新移动平均码本的存储器。 量化的线谱信息矢量从量化的目标码矢量导出。

    Method and apparatus for maintaining a target bit rate in a speech coder
    8.
    发明授权
    Method and apparatus for maintaining a target bit rate in a speech coder 有权
    用于在语音编码器中维持目标比特率的方法和装置

    公开(公告)号:US06330532B1

    公开(公告)日:2001-12-11

    申请号:US09356493

    申请日:1999-07-19

    IPC分类号: G10L2104

    CPC分类号: G10L19/002 G10L19/18

    摘要: A method and apparatus for maintaining a target bit rate in a speech coder includes a speech coder for encoding a frame at a preselected encoding rate, computing a running average bit rate for a predefined number of encoded frames, subtracting the running average bit rate from a predefined target average bit rate, and dividing the difference by the preselected encoding rate. If the quotient value is negative, a predefined number of possible occurrence counts of speech coder performance threshold values that are less than a current performance threshold value is accumulated, the accumulated number being greater than the absolute value of the quotient. The product of a decrement-per-occurrence-count-value and the predefined number of occurrence counts is subtracted from the current performance threshold value to obtain a new performance threshold value. If the quotient value is positive, a predefined number of possible occurrence counts of speech coder performance threshold values that are greater than the current performance threshold value is accumulated, the accumulated number being greater than the quotient. The product of an increment-per-occurrence-count-value and the predefined number of occurrence counts is added to the current performance threshold value to obtain a new performance.

    摘要翻译: 用于在语音编码器中维持目标比特率的方法和装置包括语音编码器,用于以预先选择的编码速率对帧进行编码,计算预定数量编码帧的运行平均比特率,从 预定义的目标平均比特率,并且将差除以预选的编码率。 如果商值为负,则累积小于当前性能阈值的语音编码器性能阈值的预定数量的可能发生计数,累积数大于商的绝对值。 从当前性能阈值中减去每次出现计数值递减和预定发生次数的乘积,以获得新的性能阈值。 如果商值为正,则累积大于当前性能阈值的语音编码器性能阈值的预定数量的可能发生计数,累积数大于商。 将每个出现次数增量值和预定发生次数的乘积加到当前性能阈值以获得新的性能。

    Fast code-vector searching
    9.
    发明授权
    Fast code-vector searching 有权
    快速码矢量搜索

    公开(公告)号:US06766289B2

    公开(公告)日:2004-07-20

    申请号:US09874657

    申请日:2001-06-04

    IPC分类号: G10L1910

    CPC分类号: G10L19/10 G10L2019/0013

    摘要: Methods and apparatus for quickly selecting an optimal excitation waveform from a codebook are presented herein. In encoding schemes that use forward and backward pitch enhancement, storage and processor load is reduced by approximating a two-dimensional autocorrelation matrix with a one-dimensional autocorrelation vector. The approximation is possible when a cross-correlation element is configured to determine the autocorrelation matrix of an impulse response and a pulse energy determination element is configured to determine the energy of a pulse code vector that incorporates secondary pulse positions.

    摘要翻译: 本文给出了从码本快速选择最佳激励波形的方法和装置。 在使用前向和后向间距增强的编码方案中,通过用一维自相关向量逼近二维自相关矩阵来减少存储和处理器负载。 当互相关元件被配置为确定脉冲响应的自相关矩阵并且脉冲能量确定元件被配置为确定包含次级脉冲位置的脉冲码矢量的能量时,近似是可能的。

    Reducing memory requirements of a codebook vector search
    10.
    发明授权
    Reducing memory requirements of a codebook vector search 有权
    减少码本向量搜索的内存要求

    公开(公告)号:US06789059B2

    公开(公告)日:2004-09-07

    申请号:US09876352

    申请日:2001-06-06

    IPC分类号: G10L1910

    CPC分类号: G10L19/10 G10L2019/0013

    摘要: Methods and apparatus for quickly selecting an optimal excitation waveform from a codebook are presented herein. To reduce the number of computations required to choose the optimal codebook vector, a subset of codevectors are selected based upon optimal pulse locations, wherein the subset of codevectors form a subcodebook. Rather than searching the entire codebook, only the entries of the subcodebook are searched.

    摘要翻译: 本文给出了从码本快速选择最佳激励波形的方法和装置。 为了减少选择最佳码本向量所需的计算次数,基于最佳脉冲位置选择码矢量的子集,其中码矢量子集形成子码本。 而不是搜索整个码本,只搜索子码本的条目。