Abstract: An encoding apparatus includes a noise detector configured to detect noise included in a certain band in accordance with an audio signal, a gain controller configured to perform gain control on the audio signal so that components in the certain band of the audio signal are attenuated when the noise is detected by the noise detector, a bit allocation calculation unit configured to calculate the numbers of bits to be allocated to frequency spectra of the audio signal which have been subjected to the gain control performed by the gain controller in accordance with the frequency spectra, and a quantization unit configured to quantize the frequency spectra of the audio signal which have been subjected to the gain control in accordance with the numbers of the bits.

Abstract: An encoding apparatus includes a noise detector configured to detect noise included in a certain band in accordance with an audio signal, a gain controller configured to perform gain control on the audio signal so that components in the certain band of the audio signal are attenuated when the noise is detected by the noise detector, a bit allocation calculation unit configured to calculate the numbers of bits to be allocated to frequency spectra of the audio signal which have been subjected to the gain control performed by the gain controller in accordance with the frequency spectra, and a quantization unit configured to quantize the frequency spectra of the audio signal which have been subjected to the gain control in accordance with the numbers of the bits.

Abstract: An encoding apparatus includes a noise detector configured to detect noise included in a certain band in accordance with an audio signal, a gain controller configured to perform gain control on the audio signal so that components in the certain band of the audio signal are attenuated when the noise is detected by the noise detector, a bit allocation calculation unit configured to calculate the numbers of bits to be allocated to frequency spectra of the audio signal which have been subjected to the gain control performed by the gain controller in accordance with the frequency spectra, and a quantization unit configured to quantize the frequency spectra of the audio signal which have been subjected to the gain control in accordance with the numbers of the bits.

Abstract: There is provided a signal processing device including a signal coincidence detection portion which detects samples, in which values based on a number of times of appearance of bits coincide with each other over a plurality of samples within a pre-set period, between a first modulated signal obtained by delaying an input signal obtained by ?? modulation and a second modulated signal obtained by subjecting the input signal to the ?? modulation again, a signal changeover portion which switches between the first modulated signal and the second modulated signal for outputting, and a switching control portion which controls the switching between the first modulated signal and the second modulated signal by the signal changeover portion in the samples in which the values based on the number of times of the appearance coincide with each other obtained by the signal coincidence detection portion.

Abstract: There is provided an audio coding device including a first windowing part that multiplies an audio signal by a first window function, a second windowing part that multiplies the audio signal by a second window function having a characteristic different from a characteristic of the first window function, a window selecting part that selects the first window function or the second window function as an optimum window function based on the audio signal multiplied by the first windowing part and the audio signal multiplied by the second windowing part, a coding part that codes a frequency spectrum of the audio signal multiplied by the optimum window function, and a transmitting part that transmits the frequency spectrum coded by the coding part and window function information representing the optimum window function.

Abstract: A decoding device includes an acquisition unit configured to acquire a first frequency signal including a narrowband signal and a wideband signal, a direct inverse orthogonal transform unit configured to perform a direct matrix operation with respect to the narrowband signal of the first frequency signal so as to perform inverse orthogonal transform, and a high-speed inverse orthogonal transform unit configured to perform inverse orthogonal transform employing a high-speed operation method with respect to the wideband signal of the first frequency signal.

Abstract: The present invention relates to a speech processing apparatus, a speech processing method and a program which, when multichannel audio signals are downmixed and coded, prevent delay and an increase in the computation amount upon decoding of the audio signals. An inverse multiplexing unit (101) acquires coded data on which a BC parameter is multiplexed. An uncorrelated frequency-time transform unit (102) performs IMDCT transform and IMDST transform of frequency spectrum coefficients of a monaural signal (XM) obtained from this coded data to generate the monaural signal XM) which is a time domain signal and a signal (XD?) which is substantially uncorrelated with this monaural signal (XM). The stereo synthesis unit (103) generates a stereo signal by synthesizing the monaural signal (XM) and the signal (XD?) using the BC parameter. The present invention is applicable to, for example, a speech processing apparatus which decodes a downmixed and coded stereo signal.

Abstract: The present invention relates to a decoding apparatus, a decoding method, an encoding apparatus, an encoding method, and programs that can shorten the delay time caused by the band extension at the time of decoding, and restrain increases in resources on the decoding side. A higher frequency component generating unit (73) generates a pseudo higher frequency spectrum by using a lower frequency spectrum (SP-L) and a higher frequency envelope (ENV-H). A phase randomizing unit (74) randomizes the phase of the pseudo higher frequency spectrum, based on a random flag (RND). An inverse MDCT unit (75) denormalizes the lower frequency spectrum (SP-L) by using a lower frequency envelope (ENV-L), and combines the pseudo higher frequency spectrum supplied from the phase randomizing unit (74) with the denormalized lower frequency spectrum (SP-L). The combination result is used as the spectrum of the entire band.

Abstract: The present invention relates to an encoding device and an encoding method, a decoding device and a decoding method, and a program that reduce deterioration of sound quality due to encoding of audio signals. An envelope emphasis part (51) emphasizes an envelope (ENV). A noise shaping part (52) divides an emphasized envelope (D) formed by emphasis of the envelope (ENV) by a value larger than 1, and subtracts noise shaping (G) specified by information (NS) from a result of the division. A quantization part (14) sets a result of the subtraction as a quantization bit count (WL), and quantizes a normalized spectrum (S1) formed by normalization of a spectrum (S0) based on the quantization bit count (WL). A multiplexing part (53) multiplexes the information (NS), a quantized spectrum (QS) formed by quantization of the normalized spectrum (S1), and the envelope (ENV). The present invention can be applied to an encoding device encoding audio signals, for example.

Abstract: The present technology relates to an encoder and an encoding method, a decoder and a decoding method, and a program by which encoding efficiency is able to be improved by constraining an appearance probability of a predetermined quantization value of an encoding target to 0 when encoding with a combination of Huffman encoding and multidimensional encoding is performed.

Abstract: A coding apparatus includes a generation unit configured to generate first coding information used for first coding of a first audio signal and second coding information used for second coding of a second audio signal, and generate third coding information used for the first coding of the second audio signal and fourth coding information used for the second coding of a third audio signal; a first coding unit configured to generate first data and second data; a second coding unit configured to generate third data and fourth data by performing the second coding on the third audio signal; and a multiplexing unit configured to generate a stream of the first audio signal and a stream of the second audio signal. The third data is decoded in place of the second data in a case where a loss or an error has occurred in the stream of the second audio signal.

Abstract: A decoding device including a decoding unit which decodes encoded data, an inverse orthogonal transformation unit which performs inverse orthogonal transformation for the encoded data and obtains a time series waveform element in a unit of blocks, a correlation calculation unit which obtains a correlation between a time series waveform element of a block arranged immediately before an error block which is a block in which an error has occurred during decoding by the decoding unit and a time series waveform element of a block arranged a predetermined number of blocks before the block, a cycle calculation unit which obtains a basic cycle of a block unit of the error block based on the correlation obtained by the correlation calculation unit, and a generation unit which generates a substitute signal of the time series waveform element of the error block.

Abstract: There is provided a voice transmitting device, including a band limiting unit that performs band limitation on an input time-series signal, a coding unit that encodes a time-series signal output from the band limiting unit, a transmitting unit that transmits a code string output from the coding unit, and a control unit that controls a band limitation operation in the band limiting unit.

Abstract: An encoding apparatus includes a time-frequency transform unit that performs a time-frequency transform on an audio signal, a normalization unit that normalizes a frequency spectral coefficient obtained by the time-frequency transform in order to generate encoded data of the audio signal, a level calculation unit that calculates a level of the audio signal, a scale factor changing unit that changes a concealment scale factor included in encoded concealment data obtained by performing, on the basis of the level of the audio signal, a time-frequency transform and normalization on a minute noise signal, the concealment scale factor being a scale factor relating to a coefficient used for the normalization, and an output unit that outputs the encoded data of the audio signal generated by the normalization unit or outputs, as encoded data of the audio signal, the encoded concealment data whose concealment scale factor has been changed.

Abstract: Provided is a signal encoding apparatus including: an encoding unit which encodes a quantization value of a frequency spectrum in an input signal through a plurality of encoding algorithms; an amplitude change amount calculation unit which calculates, for each of a plurality of subbands of the frequency spectrum, an amplitude change amount with respect to the frequency spectrum based on a spectrum envelope of the frequency spectrum; and an encoding selection unit which selects, for each subband, the encoding algorithm according to a degree of deflection of an occurrence probability distribution of the quantization value in the amplitude change amount among the plurality of the encoding algorithms.

Abstract: A signal processing device includes a bit-pattern output unit and a look-up table storage unit which are configured as follows: The bit-pattern output unit is provided for receiving input 1-bit digital signals generated by ?? modification and aligning bits of the input 1-bit digital signals in a chronological order to output parallel bit pattern. The look-up table storage unit is provided for storing a look-up table that represents a relationship between the bit patterns output from the bit pattern output unit and resulting values of a filtering arithmetic operation on the basis of the bit patterns. In the signal processing device, the bit patterns output from the bit-pattern output unit are provided as indexes. The indexes are referenced to output the resulting values of the filtering arithmetic operation corresponding to the bit patterns listed in the look-up table stored in the look-up table storage unit.

Abstract: There is provided an audio coding device which appropriately sets the quantization bit number by a small calculation amount in each stage when coding an input audio signal by performing multi-stage normalization/quantization. A quantization information calculation section determines total quantization information idwl0, based on normalization information idsf, and allocates the total quantization information idwl0 for quantization information idwl1 and quantization information idwl2. At this time, the quantization information calculation section limits the quantization information idwl1 by a limiter lim1, and allocates the total quantization information idwl0 for quantization information idwl1. If the quantization information idwl1 exceeds the limiter lim1, the excess is allocated for the quantization information idwl2. A first normalization section and a first quantization section normalizes and quantizes a frequency spectrum mdspec1 in the first stage.

Abstract: There is provided an audio coding device including a first windowing part that multiplies an audio signal by a first window function, a second windowing part that multiplies the audio signal by a second window function having a characteristic different from a characteristic of the first window function, a window selecting part that selects the first window function or the second window function as an optimum window function based on the audio signal multiplied by the first windowing part and the audio signal multiplied by the second windowing part, a coding part that codes a frequency spectrum of the audio signal multiplied by the optimum window function, and a transmitting part that transmits the frequency spectrum coded by the coding part and window function information representing the optimum window function.

Abstract: The present invention relates to a decoding apparatus, a decoding method, an encoding apparatus, an encoding method, and programs that can shorten the delay time caused by the band extension at the time of decoding, and restrain increases in resources on the decoding side. A higher frequency component generating unit (73) generates a pseudo higher frequency spectrum by using a lower frequency spectrum (SP-L) and a higher frequency envelope (ENV-H). A phase randomizing unit (74) randomizes the phase of the pseudo higher frequency spectrum, based on a random flag (RND). An inverse MDCT unit (75) denormalizes the lower frequency spectrum (SP-L) by using a lower frequency envelope (ENV-L), and combines the pseudo higher frequency spectrum supplied from the phase randomizing unit (74) with the denormalized lower frequency spectrum (SP-L). The combination result is used as the spectrum of the entire band.

Abstract: The present invention relates to a speech processing apparatus, a speech processing method and a program which, when multichannel audio signals are downmixed and coded, prevent delay and an increase in the computation amount upon decoding of the audio signals. An inverse multiplexing unit (101) acquires coded data on which a BC parameter is multiplexed. An uncorrelated frequency-time transform unit (102) performs IMDCT transform and IMDST transform of frequency spectrum coefficients of a monaural signal (XM) obtained from this coded data to generate the monaural signal XM) which is a time domain signal and a signal (XD?) which is substantially uncorrelated with this monaural signal (XM). The stereo synthesis unit (103) generates a stereo signal by synthesizing the monaural signal (XM) and the signal (XD?) using the BC parameter. The present invention is applicable to, for example, a speech processing apparatus which decodes a downmixed and coded stereo signal.