Speech signal encoding method and speech signal decoding method
First Claim
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1. A speech signal encoding method by an apparatus, the method comprising:
- specifying, by the encoding apparatus, an analysis frame in an input speech signal;
generating, by the encoding apparatus, a first modified input speech, based on the analysis frame by adding replication of all or a part of the analysis frame to the analysis frame;
applying, by the encoding apparatus, a window on the first modified input to generate a second modified input and a third modified input, each of which has a same length as the window, wherein the window is of equal length or shorter than the first modified input, and the second half of the first modified input overlaps with the first half of the second modified input, and wherein the window has a symmetrical shape that includes four sub-frames with weights w1, w2, w3 and w4, the weights satisfying the condition w1w1+w3w3=w2w2+w4w4=1;
generating, by the encoding apparatus, transform coefficients by performing a Modified Discrete Cosine Transform (MDCT) on the second and third modified inputs; and
encoding the transform coefficients by the encoding apparatus.
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Abstract
A speech signal encoding method and a speech signal decoding method are provided. The speech signal encoding method includes the steps of specifying an analysis frame in an input signal; generating a modified input based on the analysis frame; applying a window to the modified input; generating a transform coefficient by performing an MDCT (Modified Discrete Cosine Transform) on the modified input to which the window has been applied; and encoding the transform coefficient. The modified input includes the analysis frame and a self replication of all or a part of the analysis frame.
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Citations
16 Claims
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1. A speech signal encoding method by an apparatus, the method comprising:
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specifying, by the encoding apparatus, an analysis frame in an input speech signal; generating, by the encoding apparatus, a first modified input speech, based on the analysis frame by adding replication of all or a part of the analysis frame to the analysis frame; applying, by the encoding apparatus, a window on the first modified input to generate a second modified input and a third modified input, each of which has a same length as the window, wherein the window is of equal length or shorter than the first modified input, and the second half of the first modified input overlaps with the first half of the second modified input, and wherein the window has a symmetrical shape that includes four sub-frames with weights w1, w2, w3 and w4, the weights satisfying the condition w1w1+w3w3=w2w2+w4w4=1; generating, by the encoding apparatus, transform coefficients by performing a Modified Discrete Cosine Transform (MDCT) on the second and third modified inputs; and encoding the transform coefficients by the encoding apparatus. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A speech signal decoding method by a decoding apparatus, the method comprising:
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generating by the decoding apparatus, transform coefficient sequences by decoding an input speech signal, wherein the transform coefficient sequences comprise a first transform coefficient sequence and a second transform coefficient sequence; generating, by the decoding apparatus, temporal coefficient sequences by performing an Inverse Modified Discrete Cosine Transform (IMDCT) on the transform coefficients, wherein the temporal coefficient sequence includes a first temporal coefficient sequence generated from the first transform coefficient sequence by the IMDCT, and a second temporal coefficient sequence from the second transform coefficient sequence generated by the IMDCT; applying, by the decoding apparatus, a window on the first and second temporal coefficient sequences to generate a first modified sequence and a second modified sequence, respectively, wherein the second half of the first modified sequence overlaps with the first half of the second modified sequence, and wherein the window has a symmetrical shape that includes four sub-frame with weights w1, w2, w3 and w4, the weights satisfying the condition w1w1+w3w3=w2w2+w4w4=1; and outputting, by the decoding apparatus, a sample reconstructed by adding the overlapped portions of the first and second modified sequences, wherein the transform coefficient sequences are generated by applying the window to an input frame that is modified by adding replication of all or a part of the input frame to the input frame and by performing Modified Discrete Cosine Transform (MDCT). - View Dependent Claims (12, 13, 14, 15, 16)
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Specification