A METHOD OF CODING AND DECODING AUDIO SIGNALS
    1.
    发明公开
    A METHOD OF CODING AND DECODING AUDIO SIGNALS 失效
    方法用于编码和解码音频信号

    公开(公告)号:EP0910900A1

    公开(公告)日:1999-04-28

    申请号:EP96939886.0

    申请日:1996-11-21

    IPC分类号: G10L19 H04B1

    CPC分类号: G10L19/022 H04B1/665

    摘要: A method of encoding time-discrete audio signals comprises the steps of weighting the time-discrete audio signal by means of window functions overlapping each other so as to form blocks, the window functions producing blocks of a first length for signals varying weakly with time and blocks of a second length for signals varying strongly with time. A start window sequence is selected for the transition from windowing with blocks of the first length to windowing with blocks of the second length, whereas a stop window sequence is selected for the opposite transition. The start window sequence is selected from at least two different start window sequences having different lengths, whereas the stop window sequence is selected from at least two different stop window sequences having different lengths. A method of decoding blocks of encoded audio signals selects a suitable inverse transformation as well as a suitable synthesis window as a reaction to side information associated with each block.

    A METHOD OF CODING AND DECODING AUDIO SIGNALS
    2.
    发明授权
    A METHOD OF CODING AND DECODING AUDIO SIGNALS 失效
    方法用于编码和解码音频信号

    公开(公告)号:EP0910900B1

    公开(公告)日:2002-10-16

    申请号:EP96939886.6

    申请日:1996-11-21

    IPC分类号: H04B1/66

    CPC分类号: G10L19/022 H04B1/665

    摘要: A method of encoding time-discrete audio signals comprises the steps of weighting the time-discrete audio signal by means of window functions overlapping each other so as to form blocks, the window functions producing blocks of a first length for signals varying weakly with time and blocks of a second length for signals varying strongly with time. A start window sequence is selected for the transition from windowing with blocks of the first length to windowing with blocks of the second length, whereas a stop window sequence is selected for the opposite transition. The start window sequence is selected from at least two different start window sequences having different lengths, whereas the stop window sequence is selected from at least two different stop window sequences having different lengths. A method of decoding blocks of encoded audio signals selects a suitable inverse transformation as well as a suitable synthesis window as a reaction to side information associated with each block.

    VERFAHREN ZUM SIGNALISIEREN EINER RAUSCHSUBSTITUTION BEIM CODIEREN EINES AUDIOSIGNALS
    6.
    发明授权
    VERFAHREN ZUM SIGNALISIEREN EINER RAUSCHSUBSTITUTION BEIM CODIEREN EINES AUDIOSIGNALS 失效
    METHOD FOR信令的噪声替代在编码过程中的音频信号

    公开(公告)号:EP0931386B1

    公开(公告)日:2000-07-05

    申请号:EP98916947.9

    申请日:1998-03-13

    IPC分类号: H04B1/66

    CPC分类号: G10L19/028 H04B1/665

    摘要: The invention relates to a method for signalling a noise substitution during audio signal coding. According to said method, the audio signal is first transformed in the frequency range to obtain spectral values. The spectral values are subsequently grouped to form spectral value groups. On the basis of a detection whether a group of spectral values is a noise group or not, a coding table is allocated to a non-noise group or a tonal group by means of a coding table number for redundancy coding of the same. If a group is a noise group it is allocated an additional coding table number which does not refer to a coding table in order to signal that this group is a noise group and that it must not be redundancy coded. By signalling noise substitution by means of a Huffman-code table number for noise groups of spectral values which are for instance scale factor band sections and which must not be redundancy coded, an opportunity is provided for implementing availability of a noise substitution in a scale factor band in the bit flow syntax of the MPEG-2 Advanced Audio coding Standard, without intervening in the basic coding structure and without having to touch the structure of the existing bit flow syntax.

    VERFAHREN ZUM SIGNALISIEREN EINER RAUSCHSUBSTITUTION BEIM CODIEREN EINES AUDIOSIGNALS
    9.
    发明公开
    VERFAHREN ZUM SIGNALISIEREN EINER RAUSCHSUBSTITUTION BEIM CODIEREN EINES AUDIOSIGNALS 失效
    METHOD FOR信令的噪声替代在编码过程中的音频信号

    公开(公告)号:EP0931386A1

    公开(公告)日:1999-07-28

    申请号:EP98916947.0

    申请日:1998-03-13

    IPC分类号: G10L19 H03M7 H04B1

    CPC分类号: G10L19/028 H04B1/665

    摘要: The invention relates to a method for signalling a noise substitution during audio signal coding. According to said method, the audio signal is first transformed in the frequency range to obtain spectral values. The spectral values are subsequently grouped to form spectral value groups. On the basis of a detection whether a group of spectral values is a noise group or not, a coding table is allocated to a non-noise group or a tonal group by means of a coding table number for redundancy coding of the same. If a group is a noise group it is allocated an additional coding table number which does not refer to a coding table in order to signal that this group is a noise group and that it must not be redundancy coded. By signalling noise substitution by means of a Huffman-code table number for noise groups of spectral values which are for instance scale factor band sections and which must not be redundancy coded, an opportunity is provided for implementing availability of a noise substitution in a scale factor band in the bit flow syntax of the MPEG-2 Advanced Audio coding Standard, without intervening in the basic coding structure and without having to touch the structure of the existing bit flow syntax.