公开(公告)号：US20180040330A1

公开(公告)日：2018-02-08

申请号：US15725653

申请日：2017-10-05

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Takehiro MORIYA ,  Noboru HARADA ,  Yutaka KAMAMOTO

IPC: G10L19/09 ,  G10L19/032

CPC classification number: G10L19/09 ,  G10L19/032

Abstract: In encoding, pitch periods for time series signals in a predetermined time interval are calculated, and a code corresponding thereto is output. In that encoding, the resolutions for expressing the pitch periods and/or a pitch period encoding mode are switched according to whether an index indicating a periodicity and/or stationarity level of the time series signals satisfies a condition indicating high or low in periodicity and/or stationarity. In that decoding, according to whether an index indicating a periodicity and/or stationarity level, the index being included in or obtained from an input code corresponding to the predetermined time interval, satisfies a condition indicating high periodicity and/or stationarity, a decoding mode for a code, included in the input code, corresponding to pitch periods is switched to decode the code corresponding to the pitch periods to obtain the pitch periods corresponding to the predetermined time interval.

公开(公告)号：US20180040329A1

公开(公告)日：2018-02-08

申请号：US15725626

申请日：2017-10-05

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Takehiro MORIYA ,  Noboru HARADA ,  Yutaka KAMAMOTO

IPC: G10L19/09 ,  G10L19/032

CPC classification number: G10L19/09 ,  G10L19/032

Abstract: In encoding, pitch periods for time series signals in a predetermined time interval are calculated, and a code corresponding thereto is output. In that encoding, the resolutions for expressing the pitch periods and/or a pitch period encoding mode are switched according to whether an index indicating a periodicity and/or stationarity level of the time series signals satisfies a condition indicating high or low in periodicity and/or stationarity. In that decoding, according to whether an index indicating a periodicity and/or stationarity level, the index being included in or obtained from an input code corresponding to the predetermined time interval, satisfies a condition indicating high periodicity and/or stationarity, a decoding mode for a code, included in the input code, corresponding to pitch periods is switched to decode the code corresponding to the pitch periods to obtain the pitch periods corresponding to the predetermined time interval.

公开(公告)号：US20230395080A1

公开(公告)日：2023-12-07

申请号：US18032787

申请日：2020-11-05

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Ryosuke SUGIURA ,  Takehiro MORIYA ,  Yutaka KAMAMOTO

IPC: G10L19/00

CPC classification number: G10L19/0017

Abstract: A sound signal purification method includes an n-th channel signal purification step of obtaining, for each frame and for each corresponding sample t with respect to each channel n, a sequence based on a value ˜xn(t)=(1−αn)×{circumflex over ( )}xn(t)+αn×{circumflex over ( )}xM(t) obtained by adding a value αn×{circumflex over ( )}xM(t) obtained by multiplying an n-th channel purification weight an by a sample value {circumflex over ( )}xM(t) of the monaural decoded sound signal {circumflex over ( )}XM and a value (1−αn)×{circumflex over ( )}xn(t) obtained by multiplying a value (1−αn) obtained by subtracting the n-th channel purification weight αn from 1 by a sample value {circumflex over ( )}xn(t) of the n-th channel decoded sound signal {circumflex over ( )}Xn, as the n-th channel purified decoded sound signal ˜Xn.

公开(公告)号：US20230386498A1

公开(公告)日：2023-11-30

申请号：US18219562

申请日：2023-07-07

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Yutaka KAMAMOTO ,  Ryosuke SUGIURA ,  Takehiro MORIYA

IPC: G10L21/0364 ,  G10L21/0332 ,  G10L25/90

CPC classification number: G10L21/0364 ,  G10L25/90 ,  G10L21/0332

Abstract: Provided is pitch enhancement processing having little unnaturalness even in time segments for consonants, and having little unnaturalness to listeners caused by discontinuities even when time segments for consonants and other time segments switch frequently. A pitch emphasis apparatus carries out the following as the pitch enhancement processing: for a time segment in which a spectral envelope of a signal has been determined to be flat, obtaining an output signal for each of times in the time segment, the output signal being a signal including a signal obtained by adding (1) a signal obtained by multiplying the signal of a time, further in the past than the time by a number of samples T0 corresponding to a pitch period of the time segment, a pitch gain σ0 of the time segment, a predetermined constant B0, and a value greater than 0 and less than 1, to (2) the signal of the time.

公开(公告)号：US20230377585A1

公开(公告)日：2023-11-23

申请号：US18031579

申请日：2020-11-05

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Ryosuke SUGIURA ,  Takehiro MORIYA ,  Yutaka KAMAMOTO

IPC: G10L19/008 ,  G10L21/043

CPC classification number: G10L19/008 ,  G10L21/043

Abstract: There is provided a technology that improves, in a case where there is a sound signal obtained from a different code that is different from a code from which a decoded sound signal is obtained and that is derived from the same sound signal, the decoded sound signal by using the sound signal obtained from the different code. A signal (hereinafter, referred to as an upmixed common signal) obtained by upmixing a decoded sound common signal obtained by downmixing a decoded sound signal of each channel is subjected to signal purification using a signal (hereinafter, referred to as an upmixed monaural decoded sound signal) obtained by upmixing a monaural decoded sound signal to thereby generate a purified upmixed signal, and in each channel, the upmixed common signal is subtracted from the decoded sound signal and the purified upmixed signal is added thereto, to thereby generate a purified decoded sound signal.

公开(公告)号：US20230319498A1

公开(公告)日：2023-10-05

申请号：US17909666

申请日：2020-11-04

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Ryosuke SUGIURA ,  Takehiro MORIYA ,  Yutaka KAMAMOTO

IPC: H04S1/00 ,  G10L19/008

CPC classification number: H04S1/007 ,  G10L19/008 ,  H04S2400/03

Abstract: A sound signal downmix device for obtaining a downmix signal that is a signal obtained by mixing a left channel input sound signal and a right channel input sound signal includes a left-right relationship information acquisition unit 185 that obtains preceding channel information that is information indicating which of the left channel input sound signal and the right channel input sound signal is preceding and a left-right correlation coefficient that is a correlation coefficient between the left channel input sound signal and the right channel input sound signal and a downmix unit 112 that obtains the downmix signal by weighted averaging the left channel input sound signal and the right channel input sound signal to include a larger amount of an input sound signal of a preceding channel among the left channel input sound signal and the right channel input sound signal as the left-right correlation coefficient is greater, based on the preceding channel information and the left-right correlation coefficient.

公开(公告)号：US20230178086A1

公开(公告)日：2023-06-08

申请号：US18011132

申请日：2020-06-24

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Takehiro MORIYA ,  Ryosuke SUGIURA ,  Yutaka KAMAMOTO

IPC: G10L19/008 ,  G10L19/022

CPC classification number: G10L19/008 ,  G10L19/022

Abstract: There is provided such embedded encoding that the algorithmic delay of stereo coding/decoding is not larger than that of monaural coding/decoding. An encoding device (100) encodes a sound signal having a plurality of channels. A stereo encoding unit (110) obtains and outputs a stereo code representing a characteristic of difference between channels of the sound signal. A downmix unit (150) obtains a signal by mixing the sound signal as a downmix signal. A monaural encoding unit (120) encodes the downmix signal by an encoding scheme that includes processing of applying a window having overlap between frames to obtain and output a monaural code. An additional encoding unit (130) encodes a part of the downmix signal for a section corresponding to the overlap between a current frame and an immediately following frame to obtain and output an additional code.

公开(公告)号：US20230021878A1

公开(公告)日：2023-01-26

申请号：US17955980

申请日：2022-09-29

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Takehiro MORIYA ,  Yutaka KAMAMOTO ,  Noboru HARADA

IPC: G10L19/06 ,  G10L19/12

Abstract: An envelope sequence is provided that can improve approximation accuracy near peaks caused by the pitch period of an audio signal. A periodic-combined-envelope-sequence generation device according to the present invention takes, as an input audio signal, a time-domain audio digital signal in each frame, which is a predetermined time segment, and generates a periodic combined envelope sequence as an envelope sequence. The periodic-combined-envelope-sequence generation device according to the present invention comprises at least a spectral-envelope-sequence calculating part and a periodic-combined-envelope generating part. The spectral-envelope-sequence calculating part calculates a spectral envelope sequence of the input audio signal on the basis of time-domain linear prediction of the input audio signal. The periodic-combined-envelope generating part transforms an amplitude spectral envelope sequence to a periodic combined envelope sequence on the basis of a periodic component of the input audio signal in the frequency domain.

公开(公告)号：US20220116502A1

公开(公告)日：2022-04-14

申请号：US17422703

申请日：2020-01-07

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Takehiro MORIYA ,  Yutaka KAMAMOTO ,  Ryosuke SUGIURA

IPC: H04M3/56 ,  G10L19/008

Abstract: A technique is provided that can reduce degradation of the sound quality due to a tandem connection of paired coding and decoding, and can reduce the operation processing amount and the required memory amount of a multipoint control unit. In multipoint connection between terminals of a plurality of communication networks (for example, a fixed phone line and a mobile phone line) having different communication capacities, when a multichannel coding including a monaural coding scheme of a communication network having a smaller communication capacity is used in a communication network having a larger communication capacity to transmit sounds of a plurality points to the communication network terminal having the larger communication capacity, control is exercised such that monaural codes of the plurality points are output.

公开(公告)号：US20220059106A1

公开(公告)日：2022-02-24

申请号：US17414870

申请日：2019-12-09

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Ryosuke SUGIURA ,  Takehiro MORIYA ,  Yutaka KAMAMOTO

IPC: G10L19/02 ,  H03M7/30 ,  H03M7/40

Abstract: Provided is a technique for converting an integer value sequence for encoding/decoding which allows an integer value sequence having a distribution including small values other than a zero value and greatly biased to small values to be encoded with a small average bit number. Provided are: a unary coding unit which subjects an input sequence of non-negative integer values to unary coding to obtain a unary code sequence; a bit reversing unit which replaces a bit value ‘0’ with a bit value ‘1’ and a bit value ‘1’ with a bit value ‘0’ in the bits in the unary code sequence to obtain a replaced code sequence; and a unary decoding unit which subjects the replaced code sequence to unary decoding to obtain a sequence of non-negative integer values.