Abstract:
Provided is an encoding device which can reduce the encoding distortion as compared to the conventional technique and can obtain a preferable sound quality for auditory sense. In the encoding device, a shape quantization unit (111) quantizes the shape of an input spectrum with a small number of pulse positions and polarities. The shape quantization unit (111) sets a pulse amplitude width to be searched later upon search of the pulse position to a value not greater than the pulse amplitude width which has been searched previously. A gain quantization unit (112) calculates a gain of a pulse searched by the shape quantization unit (111) for each of bands.
Abstract:
An encoder generating a decoded signal with an improved quality by scalable encoding by canceling the characteristic inherent to the encoder and causing degradation of quality of the decoded signal. In the encoder, a first encoding section (102) encodes the input signal after down sampling, a first decoding section (103) decodes first encoded information outputted from the first encoding section (102), an adjusting section (105) adjusts the first decoded signal after up sampling by convoluting the first decoded signal after up sampling and an impulse response for adjustment, an adder (107) inverses the polarity of adjusted first decoded signal and adds the first decoded signal having the inverted polarity to the input signal, a second encoding section (108) encodes the residual signal outputted from the adder (107), and a multiplexing section (109) multiplexes the first encoded information outputted from the first encoding section (102) and the second encoded information outputted from the second encoding section (108).
Abstract:
PROBLEM TO BE SOLVED: To perform highly accurate pitch analysis with a small calculation amount even to a target signal with a high sampling rate.SOLUTION: This pitch analysis device for analyzing a pitch of a target signal mainly for signal analysis or signal encoding includes: a low pass filter 302 for limiting a frequency band of a target signal 301, and for outputting a transmission target signal whose frequency has been adjusted; a thinned-out correlation value calculation part 303 for extracting the signal value of a transmission target signal with a second sampling interval which is longer than a first sampling interval as the sampling interval of the target signal, and for calculating the auto-correction of the transmission target signal and the power of the transmission target signal; and a pitch determination part 304 for determining the pitch of the target signal on the basis of the calculated auto-correction and power.
Abstract:
PROBLEM TO BE SOLVED: To achieve high coding performance with relatively low computational complexity by performing searches for positions and polarities of pulses and quantization of gains in many stages to distribute proper amounts of bits for the positions and polarities as well as quantization of gains.SOLUTION: In position and polarity search processing ST21 in the first stage, positions and polarities of pulses in the case that gains of two pulses out of four pulses are ideal gains are searched. In gain VQ processing ST22 in the first stage, gains of pulses of which the positions and polarities have been searched in the position and polarity search processing ST21 in the first stage are quantized. In position and polarity search processing ST21 in the second stage, positions and polarities of pulses in the case that gains of two remaining pulses are ideal gains are searched. In gain VQ processing ST22 in the second stage, gains of pulses of which the positions and polarities have been searched in the position and polarity search processing ST21 in the second stage are quantized.
Abstract:
PROBLEM TO BE SOLVED: To implement quantization performance matching bit number and complexity with increasing bit number, and reduce a final quantization distortion by preventing a later stage from increasing a quantization distortion once reduced in an earlier stage during multistage quantization.SOLUTION: VQ sections 301, 305, 310, 315 quantize a signal to be quantized to acquire a decoded signal. Subtraction sections 302, 307, 312 subtract the decoded signal from the signal to be quantized to produce an error component which is acquired as the signal to be quantized in the following stage. Determination sections 303, 308, 313 finish the quantization if the magnitude of the error component is less than a predetermined value. A code accumulation section 317 stores codes of respective stages of quantization, and when the quantization is finished, collectively outputs the stored codes of respective stages.
Abstract:
PROBLEM TO BE SOLVED: To reduce a calculation amount when band power analysis is performed.SOLUTION: In a band power analyzer 100 which analyzes power for every plurality of bands of input signals, an autocorrelation calculation part 101 calculates finite degrees of autocorrelation by using the input signals, a fixed coefficient storage part 103 stores coefficients for every plurality of bands, which are obtained by adding a plurality of cosine coefficients calculated for every frequency to every plurality of bands, and a band power calculation part 102 calculates power for every plurality of bands by performing a product-sum operation between the finite degrees of autocorrelation and the coefficients of the bands in the respective bands of the plurality of bands.
Abstract:
PROBLEM TO BE SOLVED: To provide a voice encoding device for accurately encoding the shape of a spectrum of a signal with high tonality such as a vowel. SOLUTION: A subband composition part 151 divides a first layer error conversion coefficient to be encoded into M subbands to generate M subband conversion coefficients. A shape vector encoding part 152 encodes each of the M subband conversion coefficients to obtain M pieces of shape encoding information, and calculates each target gain of the M subband conversion coefficients. A gain vector composition part 153 composes one gain vector by using M target gains. A gain vector encoding part 154 obtains gain encoding information by encoding the gain vector. A multiplexing part 155 multiplexes shape encoding information with gain encoding information. COPYRIGHT: (C)2009,JPO&INPIT
Abstract:
PROBLEM TO BE SOLVED: To achieve an efficient use of information source codes at the time of coding time-series signals to suppress a calculation amount and improve coding performance in frequency-domain signals.SOLUTION: A first adjustment unit 102 performs a nonlinear amplitude adjustment to a first frequency spectrum. A CELP coding unit 104 generates a decoded signal by performing a CELP coding and a subsequent decoding. A second MDCT unit 105 subjects the decoded signal to an orthogonal transformation to generate a second frequency spectrum. A second adjustment unit 106 gives characteristics opposite to those which have been given to the first frequency spectrum during the amplitude adjustment in the first adjustment unit 102, to the second frequency spectrum. A subtraction unit 107 subtracts the second frequency spectrum to which the opposite characteristics have been given, from the first frequency spectrum to generate a residual spectrum. An FPC coding unit 108 codes the residual spectrum into an FPC code.