Abstract: In encoding, pitch periods for time series signals in a predetermined time interval are calculated, and a code corresponding thereto is output. In that encoding, the resolutions for expressing the pitch periods and/or a pitch period encoding mode are switched according to whether an index indicating a periodicity and/or stationarity level of the time series signals satisfies a condition indicating high or low in periodicity and/or stationarity. In that decoding, according to whether an index indicating a periodicity and/or stationarity level, the index being included in or obtained from an input code corresponding to the predetermined time interval, satisfies a condition indicating high periodicity and/or stationarity, a decoding mode for a code, included in the input code, corresponding to pitch periods is switched to decode the code corresponding to the pitch periods to obtain the pitch periods corresponding to the predetermined time interval.

Abstract: An integer value sequence is used as an input, and [1] codes corresponding to integers (referred to as specified integers) and [2] codes (referred to as extension codes) corresponding to sets of a plurality of integers other than the specified integers are previously determined. Coding is performed in such a manner that the code corresponding to the specified integer is adopted as the result of the coding if an integer value to be coded in the integer value sequence is the specified integer, and a code obtained by combining the extension code and a code obtained by applying a predetermined coding method corresponding to the extension code to the integer value to be coded is adopted as the result of the coding if the integer value to be coded in the integer value sequence is not the specified integer.

Abstract: A lossless coding technique for near-logarithmic companded PCM that achieves high compression performance is provided. In coding, the coding method that produces the smaller code amount is selected between the prediction coding method, which performs linear prediction of samples in a frame and codes the amplitude of the prediction error, and the normalization coding method, which normalizes the amplitude of the samples in the frame and codes the normalized amplitude, and a selection code that indicates the selection result is output. The samples in the frame are coded according to the selected coding method to produce a compression code. In decoding, the compression code is decoded according to a decoding process corresponding to the coding method specified by the selection code.

Abstract: A method and apparatus multiplies a past sample a time lag ? older than a current sample by a quantized multiplier ?? on a frame by frame basis, subtracts the multiplication result from the current sample, codes the subtraction result, and codes the time lag using a fixed-length coder if the multiplier ?? is smaller than 0.2 or if information about the previous frame is unavailable, or codes the time lag using a variable-length coder if ?? is not smaller than 0.2. A multiplier ? is coded by a multiplier coder and the multiplier ?? obtained by decoding the multiplier ? is outputted. The process is performed for each frame.

Abstract: On a criterion to minimize the entropy of the linear prediction residual of the input signal used for calculation of the input PARCOR coefficient sequence, PARCOR coefficients with larger absolute values are quantized with higher quantization precisions so as to reduce the increase of the code amount of the linear prediction residual caused by the quantization error of the PARCOR coefficients. If the PARCOR coefficient is represented by a value formed by a predetermined number of bits, the number of effective bits from the most significant bit toward the least significant bit included in the output value increases with the absolute value of the PARCOR coefficient.

Abstract: To improve the encoding compressibility of prediction residuals. An encoder performs prediction analysis of input time-series signals to generate prediction residuals expressed by integers, and sets an integer separation parameter that depends on the amplitude of the prediction residuals for each certain time segment. The encoder selects a side information code table corresponding to an index representing the prediction effectiveness of the time-series signals from a set of side information code tables including a side information code table used for variable length coding of side information corresponding to the separation parameter.

Abstract: An object of the present invention is to achieve high coding efficiency for a companded signal sequence and reduce the amount of codes. A coding method according to the present invention includes an analysis step and a signal sequence transformation step. The analysis step is to check whether or not there is a number that is included in a particular range but does not occur in a second signal sequence (a number sequence that indicates the magnitude (magnitude relationship) of original signals) and output information that indicates the number that does not occur.

Abstract: An object of the present invention is to achieve high coding efficiency for a companded signal sequence and reduce the amount of codes. A coding method according to the present invention includes an analysis step and a signal sequence transformation step. The analysis step is to check whether or not there is a number that is included in a particular range but does not occur in a second signal sequence (a number sequence that indicates the magnitude (magnitude relationship) of original signals) and output information that indicates the number that does not occur.

Abstract: Provided that a first segment is an earliest time segment included in a discrete time segment, and a second segment is a time segment subsequent to the first segment, a positive second-segment parameter that corresponds to a weakly monotonically increasing function value of an average amplitude of prediction residuals in a time segment including the second segment is used as a parameter for variable length coding of prediction residuals in the second segment. In addition, a value that corresponds to a weakly monotonically increasing function value of the sum of the second-segment parameter and a positive additional value that corresponds to an index representing the prediction effectiveness of time-series signals in the time segment including the second segment is used as a parameter for variable length coding of the prediction residual at a certain discrete time in the first segment.

Abstract: Information that includes first information identifying integer quotients obtained by divisions using prediction residuals or integers not smaller than 0 that increase monotonically with increases in the amplitude of the prediction residuals, as dividends, and a separation parameter decided for a time segment corresponding to the prediction residuals or a mapped integer value of the separation parameter, as a modulus, and second information identifying the remainders obtained when the dividends are divided by the modulus is generated as a code corresponding to the prediction residuals, and each piece of side information that includes the separation parameter is subjected to variable length coding.

Abstract: A method and apparatus multiplies a past sample a time lag ? older than a current sample by a quantized multiplier ?? on a frame by frame basis, subtracts the multiplication result from the current sample, codes the subtraction result, and codes the time lag using a fixed-length coder if the multiplier ?? is smaller than 0.2 or if information about the previous frame is unavailable, or codes the time lag using a variable-length coder if ?? is not smaller than 0.2. A multiplier ? is coded by a multiplier coder and the multiplier ?? obtained by decoding the multiplier ? is outputted. The process is performed for each frame.

Abstract: A frame formed of a plurality of code words encoded with an encoding mode in which two different types of code words are assigned one-to-one to two smallest quantization intervals is checked to determine whether it contains just the two types of code words assigned to the two smallest quantization intervals, and lossless encoding is applied to the frame containing just the two types of code words. A code obtained by this lossless encoding is decoded with a decoding method corresponding to the lossless encoding.

Abstract: A method and apparatus multiplies a past sample a time lag ? older than a current sample by a quantized multiplier ?? on a frame by frame basis, subtracts the multiplication result from the current sample, codes the subtraction result, and codes the time lag using a fixed-length coder if the multiplier ?? is smaller than 0.2 or if information about the previous frame is unavailable, or codes the time lag using a variable-length coder if ?? is not smaller than 0.2. A multiplier ? is coded by a multiplier coder and the multiplier ?? obtained by decoding the multiplier ? is outputted. The process is performed for each frame.

Abstract: In difference coding, each of a first to M-th channel signals is divided into frames and independent energy of every channel signal and difference energy of difference signals between all channel signals are calculated for each frame. In ascending order of energy, if a signal corresponding to an energy value is independent signal, it is determined that independent coding should be used for the signal. If the signal is a difference signal and the type of coding for one of channel signals has been determined, it is determined that the other should be difference-coded using the former channel signal as a reference signal. If the type of coding for neither of the channel signals has been determined, it is determined that one of them should be independently coded and the other should be difference-coded using the former channel signal as a reference signal.

Abstract: An object of the present invention is to achieve high coding efficiency for a companded signal sequence and reduce the amount of codes. A coding method according to the present invention includes an analysis step and a signal sequence transformation step. The analysis step is to check whether or not there is a number that is included in a particular range but does not occur in a second signal sequence (a number sequence that indicates the magnitude (magnitude relationship) of original signals) and output information that indicates the number that does not occur.

Abstract: An object of the present invention is to efficiently perform weighted difference coding of two or more signals. Determination is made as to which of independent coding and weighted difference coding is to be used for each channel so that the total energy of the channel signals and weighted difference signals is minimized. A weighted difference signal is generated on the basis of the determination and a reference signal (parent) and a weight is generated as auxiliary codes, the difference signal is treated as an input channel signal, and the process of coding determination and difference signal and auxiliary code generation is repeated. The difference signal generated at the last iteration of the process and a signal to be coded by independent coding are compressive coded and the auxiliary codes generated at the iterations of the process are coded and outputted.

Abstract: In encoding for putting one or more files and/or one or more files in a folder into a single archive file, original hierarchy information and standard hierarchy information generated by converting characters in a special character coding in each file name to characters in a standard character coding are recorded in the archive file. If the character coding used in the original hierarchy information in the archive file cannot be used in the system environment used in decoding, a file name in the standard character coding is generated from the standard hierarchy information and is converted to a character coding that can be used in the system environment.

Abstract: An object of the present invention is to efficiently perform weighted difference coding of two or more signals. Determination is made as to which of independent coding and weighted difference coding is to be used for each channel so that the total energy of the channel signals and weighted difference signals is minimized. A weighted difference signal is generated on the basis of the determination and a reference signal (parent) and a weight is generated as auxiliary codes, the difference signal is treated as an input channel signal, and the process of coding determination and difference signal and auxiliary code generation is repeated. The difference signal generated at the last iteration of the process and a signal to be coded by independent coding are compressive coded and the auxiliary codes generated at the iterations of the process are coded and outputted.

Abstract: A method and apparatus multiplies a past sample a time lag ? older than a current sample by a quantized multiplier ?? on a frame by frame basis, subtracts the multiplication result from the current sample, codes the subtraction result, and codes the time lag using a fixed-length coder if the multiplier ?? is smaller than 0.2 or if information about the previous frame is unavailable, or codes the time lag using a variable-length coder if ?? is not smaller than 0.2. A multiplier ? is coded by a multiplier coder and the multiplier ?? obtained by decoding the multiplier ? is outputted. The process is performed for each frame.

Abstract: In difference coding, each of a first to M-th channel signals is divided into frames and independent energy of every channel signal and difference energy of difference signals between all channel signals are calculated for each frame. In ascending order of energy, if a signal corresponding to an energy value is independent signal, it is determined that independent coding should be used for the signal. If the signal is a difference signal and the type of coding for one of channel signals has been determined, it is determined that the other should be difference-coded using the former channel signal as a reference signal. If the type of coding for neither of the channel signals has been determined, it is determined that one of them should be independently coded and the other should be difference-coded using the former channel signal as a reference signal.