Fujitsu Corporation

Socionext Inc.

Miyuki Shirakawa

Masanao Suzuki

Yoshiteru Tsuchinaga

Yohei Kishi

Takashi Makiuchi

Shunsuke Takeuchi

Masakiyo Tanaka

Akira Kamano

Yasuji Ota

Shusaku Ito

Jun Ono

Sosaku Moriki

Tomoya Fujita

Mari Asami

There is provided an audio encoding apparatus including a memory, and a processor coupled to the memory and the processor configured to determine whether a tone is included in a boundary between a low-frequency that is a frequency bandwidth below a predetermined frequency of an input signal and a high-frequency that is a frequency bandwidth above the predetermined frequency of the input signal, suppress a tone in one of the low-frequency and the high-frequency, encode the input signal having the low-frequency to generate a low-frequency code, encode the input signal having the high-frequency to generate a high-frequency code, and generate an encoded stream by multiplexing the low-frequency code and the high-frequency code.

Audio encoding apparatus and audio encoding method

An audio coding device that performs predictive coding on a third-channel signal included in a plurality of channels in an audio signal according to a first-channel signal and a second-channel signal, which are included in the plurality of channels, and to a plurality of channel prediction coefficients included in a coding book, the device includes a processor; and a memory which stores a plurality of instructions, which when executed by the processor, cause the processor to execute, selecting channel prediction coefficients corresponding to the first-channel signal and the second-channel signal so that an error, which is determined by a difference between the third-channel signal before predictive coding and the third-channel signal after predictive coding, is minimized; and controlling the first-channel signal or the second-channel signal so that the error is further reduced.

Audio coding device and method

An audio signal coding device divides a frequency spectrum obtained from an input digital signal to a plurality of bands, scales and quantizes divided frequency spectra based on a scalefactor of each of the bands and a common scale which is common to the plurality of bands, and codes quantized frequency spectra. The audio signal coding device includes a band number determination unit configured to calculate a number of coding bands for coding the quantized frequency spectra, and a common scale estimation unit configured to estimate the common scale in accordance with the number of coding bands.

Audio signal coding device and audio signal coding method

An audio encoding device includes a processor; and a memory which stores a plurality of instructions, which when executed by the processor, cause the processor to execute, calculating first phases indicating phases of a first channel signal and a second channel signal included in audio signals of a plurality of channels; and performing, on the basis of the first phases, either first predictive coding in which a third channel signal included in the audio signals of the plurality of channels is predicted using the first channel signal and the second channel signal or second predictive coding in which the second channel signal is predicted using the first channel signal.

Audio encoding device and audio encoding method

An audio decoding device includes a processor; and a memory which stores a plurality of instructions, which when executed by the processor, cause the processor to execute, decoding, using a first channel signal and a second channel signal included in a plurality of channels of an audio signal having a first frequency range and a second frequency range, a first prediction coefficient of the first frequency range and a second prediction coefficient of the second frequency range, both selected from a code book when prediction-encoding a third channel signal that is not subjected to prediction encoding and that is included in the plurality of channels; decoding a residual signal included in the first frequency range, the residual signal representing an error occurring in prediction encoding; and prediction-decoding the third channel signal subjected to prediction-encoding in the second frequency range from the first channel signal, the second channel signal.

Audio decoding device and audio decoding method

An audio coding device that uses a first-channel signal, a second-channel signal, and a plurality of channel prediction coefficients included in a code book, according to which predictive coding is performed on a third-channel signal, the first-channel signal, the second-channel signal, and the third-channel signal being included in a plurality of channels of an audio signal, the device includes, a processor; and a memory which stores a plurality of instructions, which when executed by the processor, cause the processor to execute, determining a distribution of error defined by a difference between the third-channel signal before predictive coding and the third-channel signal after predictive coding as a given curved surface according to the first-channel signal, the second-channel signal, and the third-channel signal before predictive coding; and calculating channel prediction coefficients, included in the code book.

An audio coding device includes a time frequency transform unit that, with respect to each of a plurality of channels included in an audio signal, generates a time frequency signal indicating frequency components at each time by performing a time frequency transform on a signal of the channel; a transient detection unit that detects a transient with respect to each of the plurality of channels so as to obtain a transient detection time; a transient time correction unit that, when a difference in transient detection times between an early detection channel in which the transient detection time is earliest and a late detection channel that is a channel other than the early detection channel among the plurality of channels is within a range in which the transient; a grid determination unit that, with respect to each of the plurality of channels, and a coding unit that codes.

Audio coding device, audio coding method, and computer-readable recording medium storing audio coding computer program

An audio coding device includes a time-to-frequency converter that performs time-to-frequency conversion on each frame of a signal in at least one channel included in an audio signal in a predetermined length of time in order to convert the signal in the at least one channel to a frequency signal; a complexity calculator that calculates complexity of the frequency signal for each of the at least one channel. The audio further includes a bit allocation controller that determines a number of bits to be allocated to each of at least one channel so that more bits are allocated to the each of the at least one channel as the complexity of the each of at least one channel increases, and increases the number of bits to be allocated as an estimation error in the number; and a coder that codes the frequency signal.

Audio coding device, method, and computer-readable recording medium storing program

A disclosed encoding device converts an audio signal into frequency spectra, determines allowable error powers with respect to bands divided by the frequency of the audio signal by a predetermined with, detects a tonal frequency spectrum from the frequency spectra, and detects a band containing the frequency spectrum. Using the detection result and the allowable error powers, the encoding device performs correction such that allowable error powers determined by a power determining unit with respect to bands adjacent to the band detected by a detecting unit become smaller than the powers of the frequency spectra with respect to the adjacent bands, and quantizes each of frequency spectra having greater powers than the corrected allowable error powers.

Audio signal encoding device, method, and medium by correcting allowable error powers for a tonal frequency spectrum

A decoding device to decode a main signal code obtained by encoding low-frequency components of an original signal and to output a lowband main signal for output of a main signal, includes: a processor; and a memory which stores a plurality of instructions, which when executed by the processor, cause the processor to execute, decoding auxiliary information code obtained by encoding auxiliary information, the auxiliary information being for generating, from the lowband main signal, a highband main signal corresponding to high-frequency components of the original signal; decoding residual code obtained by encoding low-frequency components of a residual signal indicating error components produced by encoding of the original signal, and thereby output a lowband residual signal; generating a highband residual signal indicating high-frequency components of the residual signal, based on the lowband residual signal output by the residual decoder and the output auxiliary information; generating an output signal.

Decoding device, encoding device, decoding method, and encoding method

A decoding device includes a decoder configured to separate a first signal obtained by performing down-mix on original signals of a plurality of channels, a residual signal representing a component of a difference between the original signals and the first signal, and spatial information representing the relationship among the original signals of the plurality of channels from an input signal which is obtained by multiplexing the first signal, the residual signal, and the spatial information and decode the separated encoded first signal, the encoded residual signal, and the encoded spatial information; a decorrelation signal generation unit configured to generate a decorrelation signal as decorrelation of the first signal decoded by the decoder; a residual signal determination unit configured to determine whether a level of the residual signal decoded by the decoder is equal to or smaller than a predetermined residual threshold value; a second-signal generation unit.

Decoding device and decoding method

An encoding device includes, an estimation unit to estimate a decoded signal of a plurality of channels based on a down-mix signal obtained by down-mixing an input signal of the plurality of channels, similarity between the channels of the input signal, and an intensity difference between the channels of the input signal; an analysis unit to analyze a phase of the input signal and a phase of the decoded signal; a calculation unit to calculate phase information based on the phase of the input signal and the phase of the decoded signal; and a coding unit to encode the similarity between the channels of the input signal, the intensity difference between the channels of the input signal, and the phase information.

Encoder, encoding system, and encoding method

An audio encoding device includes a time-frequency converting unit that conducts time-frequency conversion of channel signals included in an audio signal having a plurality of channels in frame units having a certain length of time to convert the channel signals to respective frequency signals; a downmixing unit that generates a main signal representing a major component of a first channel and a second channel among the plurality of channels, and a residual signal that is a component orthogonal to the main signal; a weight determining unit that obtains a decoding value predicted and a decoding value predicted, obtains signal components affecting each other between the first channel and the second channel; a weighting unit that uses the weighting coefficient; a residual signal encoding unit that encodes the weighted residual signal the weighting coefficient; and a main signal encoding unit that encodes the main signal.

Audio encoding device, audio encoding method, and computer-readable recording medium storing audio encoding computer program for encoding audio using a weighted residual signal

An audio encoding device includes, a time-frequency transform unit that transforms signals of channels included in an audio signal having a first number of channels into frequency signals respectively, a down-mix unit that generates an audio frequency signal having a second number of channels, a low channel encoding unit that generates a low channel audio code by encoding the audio frequency signal, a space information extraction unit that extracts space information representing spatial information of a sound, an importance calculation unit that calculates importance on the basis of the space information, a space information correction unit that corrects the space information, a space information encoding unit that generates a space information code, and a multiplexing unit that generates an encoded audio signal by multiplexing the low channel audio code and the space information code.

Audio encoding device, audio encoding method, and video transmission device

A downmixing device includes: a matrix conversion unit configured to perform a matrix operation for an input signal; a rotation correction unit configured to rotate an output signal of the matrix conversion unit; a spatial information extraction unit configured to extract spatial information from the output signal of the rotation correction unit; and an error calculation unit configured to calculate an error amount of the matrix operation result for the input signal by performing a matrix operation for the output signal of the rotation correction unit and the spatial information extracted by the spatial information extraction unit using a matrix that is inverse to the matrix used for the matrix operation by the matrix conversion unit.

Growing community of inventors

Fukuoka, Japan

Miyuki Shirakawa