Patent ID: 9082412
Filing Date: 2015-07-14
Classification: G10L

Abstract:
1. A decoding apparatus that receives and decodes CELP coded data generated through CELP coding and transform coded data generated through transform coding, the apparatus comprising: a memory that stores instructions; a processor that executes the instructions; a CELP decoder that decodes the CELP coded data; a first transformer that performs a modified discrete cosine transform on the decoded CELP coded data, to generate a first spectrum; a transform coding decoder that decodes the transform coded data to generate a second spectrum; an identification section that determines that one of a plurality of bands obtained by dividing frequency components of the second spectrum is a first band in which no pulse is generated by the transform coding and another of the plurality of bands is a second band next to the first band in which pulses are generated by the transform coding, using the second spectrum, and identifies degrees of a CELP suppression of an amplitude of the first spectrum for the first band and the second band based on the determination result; a suppressor that suppresses an amplitude of the first band of the first spectrum and an amplitude of the second band of the first spectrum, based on the identified degrees of the CELP suppression of the amplitude of the first spectrum, and outputs a CELP component suppressed spectrum, an adder that adds the CELP component suppressed spectrum and the second spectrum to calculate a decoded signal spectrum; and a second transformer that performs an inverse modified discrete cosine transform on the decoded signal spectrum, and outputs a decoded signal that is a speech/audio signal, wherein the degree of the suppression in the first band is a lower level than that in the second band, the identification section further determines whether a band determined to be the second band among the plurality of bands is a third band having a high pulse density or a fourth band having a low pulse density, the suppressor suppresses the first spectrum in the third band at a degree equal to or higher than suppression in the fourth band and suppresses the first spectrum in the first band at a degree lower than suppression in the fourth band, the suppressor suppresses the first spectrum at a frequency in which the pulses are not generated in the third band, at a degree higher than suppression in the fourth band, suppresses the first spectrum at a frequency in which the pulses are generated in the third band at the same degree as suppression in the fourth band, and at least one of the CELP decoder, the first transformer, the transform coding decoder, the identification section, the suppressor, the adder and the second transformer is implemented by the processor.