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 a decoded sound common signal) obtained by downmixing a decoded sound signal of each channel is subjected to signal purification using a monaural decoded sound signal to thereby generate a purified common signal, and in each channel, a signal obtained by upmixing the decoded sound common signal is subtracted from the decoded sound signal and a signal obtained by upmixing the purified common signal is added thereto, to thereby generate a purified decoded sound signal.

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.

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.

Abstract: For each frame, an n-th channel compensated decoded sound signal {tilde over (?)}X?n is obtained that is a signal obtained by compensating a high frequency of an n-th channel purified decoded sound signal {tilde over (?)}Xn obtained by performing signal processing in a time domain on an n-th channel decoded sound signal {circumflex over (?)}Xn that is a decoded sound signal of each channel of stereo obtained by decoding a stereo code CS.

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.

Abstract: A sound signal purification method includes a monaural decoded sound upmixing step of obtaining, an n-th channel upmixed monaural decoded sound signal {circumflex over (?)}XMn that is a signal obtained by upmixing a monaural decoded sound signal {circumflex over (?)}XM for each channel by an upmixing process using the monaural decoded sound signal {circumflex over (?)}XM and inter-channel relationship information that is information indicating a relationship between channels of stereo, and an n-th channel signal purification step of obtaining a sequence based on a value {tilde over (?)}xn(t) obtained by adding a value ?n×{circumflex over (?)}xMn(t) obtained by multiplying an n-th channel purification weight ?n by a sample value {circumflex over (?)}xMn(t) of the n-th channel upmixed monaural decoded sound signal {circumflex over (?)}XMn and a value obtained by multiplying a value (1??n) obtained by subtracting the n-th channel purification weight ?n from 1 by a sample value {circumflex over (?)}xn(t) of the n

Abstract: For each frame, an n-th channel compensated decoded sound signal ˜X?n is obtained that is a signal obtained by compensating a high frequency of an n-th channel purified decoded sound signal ˜Xn obtained by performing signal processing in a time domain on an n-th channel decoded sound signal {circumflex over (?)}Xn that is a decoded sound signal of each channel of stereo obtained by decoding a stereo code CS.

Abstract: For each frame, an n-th channel compensated decoded sound signal ˜X?n is obtained that is a signal obtained by compensating a high frequency of an n-th channel purified decoded sound signal ˜Xn obtained by performing signal processing in a time domain on an n-th channel decoded sound signal {circumflex over (?)}Xn (n is each integer of 1 or more and N or less) that is a decoded sound signal of each channel of stereo obtained by decoding a stereo code CS.

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??n)×{circumflex over (?)}xn(t)+?n×{circumflex over (?)}xM(t) obtained by adding a value ?n×{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??n)×{circumflex over (?)}xn(t) obtained by multiplying a value (1??n) obtained by subtracting the n-th channel purification weight ?n 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.

Abstract: For each frame, an n-th channel compensated decoded sound signal ˜X?n is obtained that is a signal obtained by compensating a high frequency of an n-th channel purified decoded sound signal ˜Xn obtained by performing signal processing in a time domain on an n-th channel decoded sound signal {circumflex over (?)}Xn obtained by decoding a stereo code CS.

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. At a terminal of a communication network having a larger communication capacity in multipoint connection between terminals in a plurality of communication networks (e.g., a fixed phone line and a mobile phone line) having different communication capacities, a multichannel coding including a monaural coding scheme of the communication network having the smaller communication capacity is performed on the coding side, whereas decoding of a multichannel-coded code of one point, decoding of a monaural-coded code of one point, or decoding of a monaural-coded code of a plurality of points is performed on the decoding side in accordance with the input code.

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.

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 ?0 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.

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 a decoded sound common signal) obtained by downmixing a decoded sound signal of each channel is subjected to signal purification using a monaural decoded sound signal to thereby generate a purified common signal, and in each channel, the decoded sound common signal is subtracted from the decoded sound signal and the purified common signal is added thereto, to thereby generate a purified decoded sound signal.

Abstract: For each frame, an n-th channel compensated decoded sound signal ˜X?n is obtained that is a signal obtained by compensating a high frequency of an n-th channel purified decoded sound signal ˜Xn obtained by performing signal processing in a time domain on an n-th channel decoded sound signal {circumflex over (?)}Xn (n is each integer of 1 or more and N or less) that is a decoded sound signal of each channel of stereo obtained by decoding a stereo code CS.

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.

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.

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.

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.

Abstract: A sequence of integer values is encoded and decoded with a number of bits of a decimal value substantially assigned per sample or/and with a smaller memory amount or calculation processing amount than in the prior art. The encoder receives the sequence of integer values as input and outputs an integer code corresponding to the sequence of integer values. An integer transformer (11) obtains one integer value (transformed integer) through algebraically-representable bijective transformation for each of a plurality of sets of integer values included in the inputted sequence of integer values. An integer encoder (12) encodes the transformed integer to thereby obtain an integer code.