摘要:
Disclosed is a spectral smoothing device with a structure whereby smoothing is performed after a nonlinear conversion has been performed for a spectrum calculated from an audio signal, and with which the amount of processing calculation is significantly reduced while maintaining excellent audio quality. With this spectral smoothing device, a sub band division unit (102) divides an input spectrum into multiple sub bands; a representative value calculation unit (103) calculates a representative value for each sub band using an arithmetic mean and a geometric mean; with respect to each representative value, a nonlinear conversion unit (104) performs a nonlinear conversion the characteristic of which is further emphasized as the value increases; and a smoothing unit (105) that smoothes the representative value which has undergone the nonlinear conversion for each sub band, at the frequency domain.
摘要:
There is disclosed an audio decoding device capable of improving audio quality of a decoded signal by considering the energy change of a past signal in eracure concealment processing. In this device, an energy change calculation unit (143) calculates an average energy of an audio source signal of one-pitch cycle from the end of the ACB vector outputted from an adaptive codebook (106). Moreover, the energy change calculation unit (143) calculates a ratio of the average energy of the current sub-frame and the sub-frame immediately before and outputs the ratio to an ACB gain generation unit (135). The ACB gain generation unit (135) outputs a conceal processing ACB gain defined by the ACB gain decoded in the past or information on the energy change ratio outputted from the energy change calculation unit (143) to a multiplier (132).
摘要:
The objective of the present invention is to suppress deterioration of call quality caused by transcoding without interrupting a call even if a codec used by one of the terminals during communication is changed. A modification determination unit, in the case of detecting a modification of a codec used by one terminal of two terminals, determines whether or not to constrain the bandwidth of the first codec using a first codec of the other terminal and a second codec after modification by the first-mentioned one of the terminals. A signaling generation unit transmits, to the other terminal, signaling for limiting the bandwidth if the bandwidth is to be limited.
摘要:
A decoding device reduces abrupt changes in the number of channels in a decoded signal when transmission errors occur as a result of lost frames in an encoding/decoding system for multichannel signals. In the device, a demultiplexer receives an encoded monaural signal and an encoded differential signal and detects change over time in the received encoded differential signal. An M signal decoder decodes the encoded monaural signal and obtains a decoded monaural signal. An S signal decoder decodes the encoded differential signal and obtains a decoded differential signal. A smoothing unit performs smoothing on the decoded differential signal by means of a computation involving the decoded differential signal and coefficients corresponding to the change over time detected by the demultiplexer. An L/R signal computation unit computes a decoded stereo signal from the decoded monaural signal and the smoothed decoded differential signal.
摘要翻译:由于多通道信号的编码/解码系统中的丢失帧的结果,当传输错误发生时,解码装置减少解码信号中的信道数量的突然变化。 在该装置中,解复用器接收经编码的单声道信号和经编码的差分信号,并检测接收到的编码差分信号中随时间的变化。 M信号解码器解码编码的单声道信号并获得解码的单声道信号。 S信号解码器对编码的差分信号进行解码并获得解码的差分信号。 平滑单元通过涉及解码的差分信号的计算和对应于由解复用器检测到的随时间变化的系数对解码的差分信号进行平滑处理。 L / R信号计算单元从解码的单声道信号和平滑的解码的差分信号计算解码的立体声信号。
摘要:
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.
摘要:
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.
摘要:
A vector quantizer which improves the accuracy of vector quantization in switching over a vector quantization codebook on a first stage depending on the type of feature having the correlation with a quantization target vector. In the vector quantizer, a classifier generates classification information representing a type of narrowband LSP vector having the correlation with wideband LSP (Line Spectral Pairs) of the plural types. A first codebook selects one sub-codebook corresponding to the classification information as a codebook used for the quantization of the first stage from plural sub-codebooks corresponding to each of the types of narrowband LSP vectors. A multiplier multiplies the quantization residual vector of the first stage inputted from an adder by a scaling factor corresponding to the classification information of plural scaling factors stored in a scaling factor determiner and outputs it to an adder as the quantization target of a second stage.
摘要:
There is disclosed a scalable encoding device capable of increasing the conversion performance from a narrow-band LSP to a wide-band LSP (prediction accuracy when predicting the wide-band LSP from the narrow-band LSP) and realizing a high-performance band scalable LSP encoding. The device includes a conversion coefficient calculation unit (109) for calculating a conversion coefficient by using a narrow-band quantization LSP which has been outputted from a narrow-band LSP encoding unit (103) and a wide-band quantization LSP which has been outputted from a wide-band LSP encoding unit (107). The wide-band LSP encoding unit (107) multiplies the narrow-band quantization LSP with the conversion coefficient inputted from the conversion coefficient calculation unit (109) so as to convert it into a wide-band LSP. The wide-band LSP is multiplied by a weight coefficient to calculate a prediction wide-band LSP. The wide-band LSP encoding unit (107) encodes an error signal between the obtained prediction wide-band LSP and the wide-band LSP so as to obtain a wide-band quantization LSP.
摘要:
There is disclosed an encoder apparatus whereby, when a band expanding technique for encoding, based on the spectral data of a lower frequency portion, the spectral data of a higher frequency portion is applied to a lower layer in a hierarchical encoding/decoding system, an efficient encoding can be performed in an upper layer as well, thereby improving the decoded-signal quality. In an encoder apparatus (101), a second layer decoder unit (207) calculates a spectrum (differential spectrum), which is to be encoded in a third layer encoder unit (210) that is an upper layer of the second layer decoder unit (207), by applying such an ideal gain (first gain parameter a1) that minimizes the energy of the differential spectrum.
摘要:
An encoding apparatus and method for generating low-frequency-band encoding information and high-frequency-band encoding information from an original signal. The encoding apparatus includes a first spectrum calculator that calculates a first spectrum of a low frequency band from a decoded signal of the low-frequency-band encoding information, a second spectrum calculator that calculates a second spectrum from the original signal, an estimator that divides a high frequency band of the second spectrum into a plurality of bands and estimates the second spectrum included in each band, using the first spectrum, and a first error component encoder that encodes a first error component between the high frequency band of the second spectrum and an estimated spectrum. A corresponding decoding apparatus and method provides decoding.