Nippon Telegraph and Telephone Corporation

Matsushita Electric Industrial Co., Ltd.

Panasonic Corporation

Yusuke Hiwasaki

Masahiro Fukui

Takehiro Moriya

Yutaka Kamamoto

Noboru Harada

Hiroyuki Ehara

Takeshi Mori

Kazutoshi Yasunaga

Kimitaka Tsutsumi

Shigeaki Sasaki

Kazunori Mano

Hitoshi Ohmuro

Akitoshi Kataoka

Toshiyuki Morii

In encoding, a frequency-domain sample sequence derived from an acoustic signal is divided by a weighted envelope and is then divided by a gain, the result obtained is quantized, and each sample is variable-length encoded. The error between the sample before quantization and the sample after quantization is quantized with information saved in this variable-length encoding. This quantization is performed under a rule that specifies, according to the number of saved bits, samples whose errors are to be quantized. In decoding, variable-length codes in an input sequence of codes are decoded to obtain a frequency-domain sample sequence; an error signal is further decoded under a rule that depends on the number of bits of the variable-length codes; and from the obtained sample sequence, the original sample sequence is obtained according to supplementary information.

Encoding method, decoding method, encoder, decoder, program, and recording medium

A normalization value calculatorcalculates a normalization value that is representative of a predetermined number of input samples. A normalization value quantizerquantizes the normalization value to obtain a quantized normalization value and a normalization-value quantization index corresponding to the quantized normalization value. An quantization-candidate calculatorsubtracts a value corresponding to the quantized normalization value from a value corresponding to the magnitude of each of the samples to obtain a difference value and, when the difference value is positive and the value of each of the samples is positive, sets the difference value as an quantization candidate corresponding to the sample. When the difference value is positive and the value of each of the samples is negative, the quantization-candidate calculatorreverses the sign of the difference value and setting the sign-reversed value as an quantization candidate corresponding to the sample. When the difference value is not positive, the quantization-candidate calculatorsets 0 as an quantization candidate corresponding to the sample. A vector quantizerjointly vector-quantizes a plurality of quantization candidates corresponding to a plurality of samples to obtain a vector quantization index.

Coding method, decoding method, apparatus, program, and recording medium

A frequency-domain sample interval corresponding to a time-domain pitch period L corresponding to a time-domain pitch period code of an audio signal in a given time period is obtained as a converted interval T, a frequency-domain pitch period T is chosen from among candidates including the converted interval Tand integer multiples U&#xd7;Tof the converted interval T, and a frequency-domain pitch period code indicating how many times the frequency-domain pitch period T is greater than the converted interval Tis obtained. The frequency-domain pitch period code is output so that a decoding side can identify the frequency-domain pitch period T.

Long-term prediction and frequency domain pitch period based encoding and decoding

Frequency domain pitch period based encoding and decoding in accordance with magnitude and amplitude criteria

Encoding method, decoding method, encoder, decoder, program and recording medium

An encoding technique encoding a sound signal at a low bit rate with reduced processing. The technique includes: an interval determination determining an interval T between samples corresponding to periodicity of an audio signal or an integer multiple of a fundamental frequency of the audio signal from a set S of candidates for the interval T; and a side information generating encoding the determined interval T to obtain side information. The interval determining determines the interval T from a set S of Y candidates (Y&#x3c;Z) including Zcandidates (Z&#x3c;Z) selected from among Z candidates for the interval T representable with the side information without depending on a candidate subjected to the interval determination in a previous frame a predetermined number of frames before the current frame and including a candidate subjected to the interval determination in the previous frame the predetermined number of frames before the current frame.

Encoding method, encoder, periodic feature amount determination method, periodic feature amount determination apparatus, program and recording medium

In a speech coding scheme based on a speech production model, such as a CELP-based scheme, an object of the present invention is to provide a decoding method that can reproduce natural sound even if the input signal is a noise-superimposed speech. The decoding method includes a speech decoding step of obtaining a decoded speech signal from an input code, a noise generating step of generating a noise signal that is a random signal, and a noise adding step of outputting a noise-added signal, the noise-added signal being obtained by summing the decoded speech signal and a signal obtained by performing, on the noise signal, a signal processing that is based on at least one of a power corresponding to a decoded speech signal for a previous frame and a spectrum envelope corresponding to the decoded speech signal for the current frame.

Decoding method, decoding apparatus, program, and recording medium therefor

A value of gain is updated so that the greater the difference between the number of bits or estimated number of bits in a code obtained by encoding a string of integer value samples obtained by dividing each sample in a sample string derived from an input audio signal in a given interval by gain before the update and a predetermined number B of allocated bits, the greater the difference between the gain before the update and the updated gain. A gain code corresponding to the updated gain and an integer signal code obtained by encoding a string of integer value samples obtained by dividing each sample in the sample string by the gain are obtained.

Encoding method, encoder, program and recording medium

In encoding, index information indicating a group of coefficients that minimizes the sum of the error between the value of each sample and the value is obtained by multiplying the quantized value of each of a plurality of samples by a coefficient corresponding to the position of the sample. The coefficient is selected from a plurality of groups of predetermined coefficients corresponding to the positions of the samples. In decoding, a plurality of values corresponding to an input vector quantization index are obtained as decoded values corresponding to a plurality of sample positions. With the use of a group of predetermined coefficients corresponding to the plurality of sample positions and indicated by input index information, the values obtained by multiplying the decoded values and the coefficients, corresponding to the sample positions are output.

Encoding method, decoding method, encoding device, decoding device, and recording medium for a plurality of samples

In encoding, the number of bits to be assigned to codes corresponding to noise or a pulse sequence obtained according to prediction analysis applied to time series signals included in a predetermined time interval is switched according to whether an index that indicates a level of periodicity and/or stationarity of input time series signals satisfies a condition that indicates high periodicity and/or high stationarity or a condition that indicates low periodicity and/or low stationarity, to acquire the codes corresponding to the noise and the pulse sequence. In decoding, a decoding mode for codes corresponding to noise or a pulse sequence included in codes corresponding to a predetermined time interval is switched according to the same criterion as that described above to decode the codes corresponding to the noise or the pulse sequence to acquire noise or a pulse sequence corresponding to the predetermined time interval.

Encoding method for acquiring codes corresponding to prediction residuals, decoding method for decoding codes corresponding to noise or pulse sequence, encoder, decoder, program, and recording medium

A coding method with a small error is provided. In the coding method of the present invention, a normalization value obtained from an input signal is corrected for an error calculated from an input and output in vector quantization and is then quantized. The coding method includes a normalization stage of normalizing the input signal in accordance with the normalization value of the input signal, calculated in each frame; a dividing stage of dividing the normalized frame into divided input signal sequences in accordance with a predetermined rule; a vector quantization stage of applying vector quantization to the divided input signal sequences to generate a vector quantization index; and a normalization value correction stage of correcting the normalization value of the input signal for the error obtained from the input and output in the vector quantization stage.

Coding method, decoding method, apparatuses thereof, programs thereof, and recording medium

A plurality of samples are vector-quantized to obtain a vector quantization index and quantized values; bits are assigned in a predetermined order of priority based on auditory perceptual characteristics to one or more sets of sample positions among a plurality of sets of sample positions, each set having a plurality of sample positions and being given an order of priority based on the auditory perceptual characteristics, the number of bits not being larger than the number of bits obtained by subtracting the number of bits used for a code corresponding to the vector quantization index from the number of bits assigned for the code corresponding to the vector quantization index; and index information indicating a group of coefficients that minimizes the sum of the error between the value of each sample included in each of the sets of sample positions to which the bits are assigned and the value obtained by multiplying the quantized value of each sample included in the set of sample positions by a coefficient corresponding to the position of the sample, of all the sample positions included in the set of sample positions, is output.

Encoding method, decoding method, encoding device, decoding device, program, and recording medium

When acoustic signal packets are communicated over an IP communication network, data corresponding to an acoustic signal (acoustic signal corresponding data) has been included and transmitted in a packet different from a packet containing the acoustic signal. However, conventionally, a packet in which the acoustic signal corresponding data is to be included must be determined beforehand and cannot dynamically be changed. According to the present invention, the amount of delay of acoustic signal corresponding data with respect to an acoustic signal is contained in an acoustic signal packet as delay amount control information. Furthermore, the conditions of a communication network are detected from the number of packets lost in a burst loss or jitters and the number of the packets to be stored and the amount of delay at the receiving end are thereby determined.

Growing community of inventors

Tokyo, Japan

Yusuke Hiwasaki