摘要:
An encoder apparatus is provided that suppresses the quality degradation of encoding processes. An ultimate selection candidate limiting unit 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, which uses the designated suppression factors to generate a suppressed spectrum. A CELP residual signal spectrum calculating unit, to which the suppressed spectrum is input, calculates a residual spectrum. A conversion encoding unit uses the residual spectrum to perform a second encoding process. A distortion evaluating unit 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.
摘要:
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.
摘要:
An encoding device and encoding method improve a quality of a decoded signal under very low bit rate conditions using a small amount of computation. A spectrum corrector performs correction processing on a subspectrum in each subband in such a manner that samples equal to or greater than a subspectrum average value are left unchanged and samples smaller than the subspectrum average value are replaced by zero. As a result of this, it is possible to significantly reduce the number of bits required to quantize the subspectrums without a substantial reduction in quality in a local searcher and in a multi-rate indexer.
摘要:
An encoding device, a decoding device, and related methods are provided that eliminate the loss of synchronization of the adaptive filters of a terminal at the encoding end and a terminal at the decoding end caused by transmission errors. Deterioration of the sound quality is suppressed when a multiple channel signal is encoded with high efficiency using an adaptive filter. In the terminal at the encoding end, a buffer stores updated filter coefficients. When packet loss detection information indicating whether there is any packet loss in the terminal at the decoding end indicates that there is packet loss, a switch outputs the past filter coefficients of the previous (NX+1) frames from the buffer to an adaptive filter. The adaptive filter uses the past filter coefficients of the previous (NX+1) frames to conduct filtering.
摘要:
An encoding device is provided for increasing the quality of an encoded signal, even when encoding music signals. In the encoding device, a Code-Excited Linear Prediction (CELP) encoder generates first encoded data by encoding an input signal, and a CELP decoder generates a decoded signal by decoding the first encoded data input from the CELP encoder. Additionally, a characteristic parameter encoder calculates a parameter that expresses the degree of fluctuation in the ratio of the peak components and the floor components between the spectra of the decoded signal and the input signal.
摘要:
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.
摘要:
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. The encoding device (101) includes: a band division process unit (201) which subjects an input signal to a band division process so as to obtain a lower intermediate-range component lower than a first frequency and a high-range component higher than the first frequency; a low-range encoding unit (202) which suppresses a portion of the lower intermediate-range component higher than a second frequency so as to obtain a low-range component and encodes the low-range component so as to obtain low-range encoded information; an intermediate-range correction unit (203) corrects the intermediate-range component higher than the second frequency among the suppressed lower intermediate-range component so as to obtain a corrected intermediate-range component; an intermediate high-range encoding unit (204) which encodes the corrected intermediate-range component and the high-range component so as to obtain intermediate high-range encoded information; and a multiplexing unit (205) which multiplexes the low-range encoded information and the intermediate high-range encoded information so as to obtain encoded information.
摘要:
Disclosed is an encoding device whereby it is possible to improve the quality of an encoded signal, even when encoding music signals. In the encoding device, a Code-Excited Linear Prediction (CELP) encoder (101) generates first encoded data by encoding an input signal, a CELP decoder (102) generates a decoded signal by decoding the first encoded data input from the CELP encoder (101), and a characteristic parameter encoder (106) calculates a parameter that expresses the degree of fluctuation in the ratio of the peak components and the floor components between the spectra of the decoded signal and the input signal.
摘要:
A transform coding apparatus includes an input scale factor calculating section that calculates an input scale factor having a predetermined number of scale factors associated with an input spectrum as an element, and a codebook that stores a plurality of scale factor candidates having a predetermined number of elements and outputs one scale factor candidate. The transform coding apparatus also includes an error calculating section that calculates an error on a per element basis, a weighted error calculating section that determines a weight on a per element basis and calculates a sum of products of the error and the weight to calculate a weighted error, and a searching section that searches for a scale factor candidate that minimizes the weighted error in the codebook.
摘要:
Disclosed are an encoding device and a decoding device which suppress the occurrence of pre-echo artifacts and post-echo artifacts caused by a high layer having a low temporal resolution, and which implement high subjective quality encoding and decoding. An encoding device (100) carries out scalable coding comprising a low layer, and a high layer having a lower temporal resolution than that of the low layer. A start point detection unit (or end point detection unit) (150) determines the start point (or end point) of sections of the decoded low layer signal which have audio, and when the start point (or end point) is determined, a second layer encoding unit (160) selects a bandwidth to be excluded from encoding on the basis of the spectral energy from the decoded first layer signal, excludes the selected bandwidth, and encodes an error signal.