Abstract: A decoding device is capable of flexibly calculating high-band spectrum data with a high accuracy in accordance with an encoding band selected by an upper-node layer of the encoding side. In this device: a first layer decoder decodes first layer encoded information to generate a first layer decoded signal; a second layer decoder decodes second layer encoded information to generate a second layer decoded signal; a spectrum decoder performs a band extension process by using the second layer decoded signal and the first layer decoded signal up-sampled in an up-sampler so as to generate an all-band decoded signal; and a switch outputs the first layer decoded signal or the all-band decoded signal according to the control information generated in a controller.

Abstract: A voice encoding device accurately encodes a spectrum shape of a signal having a strong tonality such as a vowel. The device includes: a sub-band divider which divides a first layer error conversion coefficient to be encoded into M sub-bands so as to generate M sub-band conversion coefficients; a shape vector encoder which performs encoding on each of the M sub-band conversion coefficients so as to obtain M shape encoded information and calculates a target gain of each of the M sub-band conversion coefficients; a gain vector former which forms one gain vector by using M target gains; a gain vector encoder which encodes the gain vector so as to obtain gain encoded information; and a multiplexer which multiplexes the shape encoded information with the gain encoded information.

Abstract: Disclosed is an encoding device which can accurately specify a band having a large error among all the bands by using a small calculation amount. A first position identifier uses a first layer error conversion coefficient indicating an error of a decoding signal for an input signal so as to search for a band having a large error in a relatively wide bandwidth in all the bands of the input signal and generates first position information indicating the identified band. A second position identifier searches for a target frequency band having a large error in a relatively narrow bandwidth in the band identified by the first position identifier and generates second position information indicating the identified target frequency band. An encoder encodes a first layer decoding error conversion coefficient contained in the target frequency band.

Abstract: There is disclosed an encoding device capable of improving similarity between the high frequency band spectrum of the original signal and a new spectrum to be generated while realizing a low bit rate when encoding a wide-band signal spectrum. The encoding device has sub-band amplitude calculation units for calculating the amplitude of the respective sub-bands for the high frequency band spectrum obtained from the wide-band signal. A search unit and a gain codebook select some sub-bands from a plurality of sub-bands and only the gain of the selected sub-bands is subjected to encoding. An interpolation unit expresses the gain of the sub-band not selected, by mutually interpolating the selected gains.

Abstract: Provided is a stereo signal encoding device that enables a lower bitrate without decreasing quality when applying an intermittent transmission technique to a stereo signal. A stereo encoding unit (103) generates first stereo encoded data by encoding the stereo signal when the stereo signal of the current frame is an audio section A stereo DTX encoding unit (104) is a means for encoding the stereo signal when the stereo signal of the current frame is a non-audio section, and generates second stereo encoded data by encoding each of: a monaural signal spectral parameter that is a spectral parameter of a monaural signal generated using the first channel signal and the second channel signal; first channel signal information relating to the first channel signal; and second channel signal information relating to the second channel signal.

Abstract: An encoding device enables the amount of processing operations to be significantly reduced while minimizing deterioration in the quality of an output signal. This encoding device (101) encodes an input signal by determining the correlation between a first signal generated by using the input signal and a second signal generated by a predetermined method. An importance assessment unit (202) sets the importance of each of a plurality of processing units obtained by dividing the frames of the input signal. A CELP coder (203) performs sparse processing in which the amplitude value of a predetermined number of samples among multiple samples constituted by the first signal and/or the second signal in each processing unit is set to zero according to the importance that was set for each processing unit, and calculates the correlation between the first signal and the second signal, either of which was subjected to sparse processing.

Abstract: Provided is an audio encoding device that can suppress degradation of audio quality. Spectral coefficients of synthesized signal from CELP core layer are utilized to fulfill spectral gaps in error signal spectrum coefficients from a transform coding layer. By both spectral coefficients, decoded signal spectral coefficients are generated. The decoded signal spectral coefficients and the input signal spectral coefficients are divided into a plurality of sub bands. In each sub band, the energy of the input signal spectral coefficient corresponding to a zero decoded error signal spectral coefficient is calculated, and the energy of the decoded signal spectral coefficient corresponding to the zero decoding error signal spectral coefficient is calculated, and their energy ratio is calculated and is quantized and transmitted.

Abstract: Provided is an encoder apparatus that can suppress the quality degradation of encoding processes. An ultimate selection candidate limiting unit (109) uses the spectrum of an input signal and a residual spectrum to designate a given number of pre-selected suppression factors to a CELP component suppressing unit (104); the CELP component suppressing unit (104) uses the designated suppression factors to generate a suppressed spectrum; a CELP residual signal spectrum calculating unit (105), to which the suppressed spectrum is input, calculates a residual spectrum; a conversion encoding unit (110) uses the residual spectrum to performs a second encoding process; and a distortion evaluating unit (112) determines one of the designated suppression factors by use of the spectrum of a second decoded signal generated by decoding a second code obtained by the second encoding process and further by use of the suppressed spectrum and the spectrum of the input signal.

Abstract: There is disclosed an encoding device capable of improving similarity between the high frequency band spectrum of the original signal and a new spectrum to be generated while realizing a low bit rate when encoding a wide-band signal spectrum. The encoding device has sub-band amplitude calculation units (122, 128) for calculating the amplitude of the respective sub-bands for the high frequency band spectrum obtained from the wide-band signal. A search unit (124) and a gain codebook (125) select some sub-bands from a plurality of sub-bands and only the gain of the selected sub-bands is subjected to encoding. An interpolation unit (126) expresses the gain of the sub-band not selected, by mutually interpolating the selected gains.

Abstract: It is possible to improve quality of a decoding signal in a band spread for estimating a high band from a low band of a decoding signal. A first layer encoder encodes a lower band portion below a predetermined frequency of an input signal so as to generate first layer encoded information. A first layer decoder decodes the first layer encoded information so as to generate a first layer demodulated signal. A second layer encoder divides a high band portion higher, than a predetermined frequency, of an input signal into a plurality of sub-bands and estimates each of the sub-bands from the input signal or the first layer decoded signal by using the estimation result of the sub-band adjacent to the lower band side so as to generate second encoded information including the estimation results of the sub-bands.

Abstract: Provided are a coding device, a decoding device, and methods thereof, with which it is possible to implement high sound quality coding and decoding in layered coding (scalable coding or embedded coding) wherein each layer comprises a plurality of bit rates (multi-rate). In the coding device (100), a feature analysis unit (101) extracts feature values of an input signal. Then a bit rate determination unit (102) determines, on the basis of the feature values of the input signal, a combination of a coding rate (low region coding rate) of a low region signal coding unit (104) which carries out coding of a low region part of the input signal and a coding rate (high region coding rate) of a high region signal coding unit (105) which carries out coding of a high region part of the input signal.

Abstract: Disclosed is a decoding device which can efficiently encode/decode spectral data in a high pass section of a broadband signal. In the disclosed device: a sample group extraction unit (372) partially selects spectral components by means of an ease of selection importance which is the extent that the spectral components come close to the spectral component having the maximum amplitude value, in the spectrum of a high pass estimated by means of first parameters contained in second encoded information and bands most approximated to each of the spectrums of a plurality of sub-bands calculated from the spectrum of a second decode signal; a logarithmic gain application unit (373) applies second parameters to the partially selected spectral components; and an interpolation processing unit (374) applies third parameters which are adaptively set according to the value of the second parameters, to the spectral components which were not partially selected.

Abstract: This invention introduces apparatus and methods to efficiently encode the quantization parameters of split multi-rate lattice vector quantization. In this invention, by doing spectral analysis on the split multi-rate vector quantized spectrum, the spectrum is split to null vectors region and non-null vectors region. For the null vectors region, instead of transmitting series of indication for null vectors, an indication of null vectors region and the quantized value of index of the ending vector in the null vectors region (or the number of the null vectors in the null vectors region) are transmitted. The indication of null vectors region can be designed in many ways, the only requirement is the indication should be distinguishable in the decoder side. The ending index or the number of null vectors can be quantized by an adaptively designed codebook. By applying of the invented method, some bits can be saved from the codebook indications.

Abstract: An encoder capable of reducing the degradation of the quality of the decoded signal in the case of band expansion in which the high band of the spectrum of an input signal is estimated from the low band. In this encoder, a first layer encoder encodes an input signal and generates first encoded information, a first layer decoder decodes the first encoded information and generates a first decoded signal, a characteristic judger analyzes the intensity of the harmonic structure of the input signal and generates harmonic characteristic information representing the analysis result, and a second layer encoder changes, on the basis of the harmonic characteristic information, the numbers of bits allocated to parameters included in second encoded information created by encoding the difference between the input signal and the first decoded signal before creating the second information.

Abstract: Provided is an encoding device which divides an input signal into a low-range component and a high-range component and encodes the components in separate encoding units. The encoding device can improve quality of a decoded signal.

Abstract: There is disclosed an encoding device capable of appropriately adjusting the dynamic range of spectrum inserted according to the technique for replacing a spectrum of a certain band with a spectrum of another band. The device includes a spectrum modification unit (112) which modifies a first spectrum S1(k) of the band 0?k<FL in various ways to change the dynamic range so that a way of modification for obtaining an appropriate dynamic range is checked. The information concerning the modification is encoded and given to a multiplexing unit (115). By using a second spectrum S2(k) having a valid signal band 0?k.

Abstract: Disclosed is a decoder capable of improving the sound quality of a decoded sound signal in an encoding method which combines speech encoding and music encoding in a hierarchical structure. A transform-encoding decoding unit (202) decodes transform-encoded data to generate a spectrum of a decoded transform-encoded signal. A band decision unit (203) uses the spectrum of the decoded transform-encoded signal to decide whether each of a plurality of bands in which frequency components of an input signal are divided constitute a first band in which a transform encoded pulse is not established or a second band in which said pulse is established. A CELP component suppression unit (207) suppresses the spectrum of a CELP decoded signal, which is the frequency component of a decoded signal of CELP encoded data, to the extent that suppression in the first band is weaker than suppression in the second band.

Abstract: There is provided an audio encoding device capable of maintaining continuity of spectrum energy and preventing degradation of audio quality even when a spectrum of a low range of an audio signal is copied at a high range a plurality of times. The audio encoding device (100) includes: an LPC quantization unit (102) for quantizing an LPC coefficient; an LPC decoding unit (103) for decoding the quantized LPC coefficient; an inverse filter unit (104) for flattening the spectrum of the input audio signal by the inverse filter configured by using the decoding LPC coefficient; a frequency region conversion unit (105) for frequency-analyzing the flattened spectrum; a first layer encoding unit (106) for encoding the low range of the flattened spectrum to generate first layer encoded data; a first layer decoding unit (107) for decoding the first layer encoded data to generate a first layer decoded spectrum, and a second layer encoding unit (108) for encoding.

Abstract: A coding apparatus reduces a circuit scale and the amount of coding processing calculation. A frequency domain conversion section performs a frequency analysis of the signal sampled at a sampling rate Fx with an analysis length of 2·Na and calculates first spectrum S1(k)(0?k<Na). A band extension section extends the effective frequency band of first spectrum S1(k) to 0?k<Nb so that a new spectrum can be assigned to the extended area following to the frequency k=Na of first spectrum S1(k). An extended spectrum assignment section assigns extended spectrum S1?(k)(Na?k<Nb) input to the extended frequency band from the outside. A spectral information specification section outputs information necessary to specify extended spectrum S1?(k) out of the spectrum given from the extended spectrum assignment section as a code.

Abstract: Disclosed is an encoding device capable of improving decoded signal quality. A local search unit (302) conducts a local search on a plurality of sub-bands generated by dividing spectrum data, and calculates lattice vectors for the spectra in the plurality of sub-bands. A multi-rate indexing unit (303) uses the lattice vectors to perform multi-rate indexing on each of the sub-bands, and generates indexing information showing the results thereof. A band selection unit (304) determines certain sub-bands from amongst the plurality of sub-bands in a plurality of encoding layers as perceptually important sub-band groups, where these are: within a selection range of sub-bands wherein the total number of encoding bits allocated to each of the plurality of sub-bands in the indexing information is equal to or less than an already set value, and within a sub-band selection range with the highest total energy of each of the plurality of sub-bands.