Speech audio encoding device, speech audio decoding device, speech audio encoding method, and speech audio decoding method
First Claim
1. A speech/audio coding apparatus, comprising:
- a receiver that receives a time-domain speech input signal;
a processor thattransforms a time-domain speech input signal into a frequency-domain spectrum;
divides a frequency region of the spectrum in an extended band into a plurality of bands;
sets a limited band for each divided band in the current frame, when a difference between a first frequency with a first maximum amplitude in a spectrum of the divided band in a preceding frame and a second frequency with a second maximum amplitude in a spectrum of the divided band in a current frame is below a threshold, a width of the limited band in the current frame being narrower than the divided band and the limited band including the first frequency; and
encodes the spectrum in the limited band within each divided band in the current frame, and does not encode a spectrum outside the limited band within each divided band in the current frame.
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Abstract
A speech/audio coding apparatus is provided that includes a receiver that receives a time-domain speech input signal and a processor. The processor transforms a time-domain speech input signal into a frequency-domain spectrum, and divides a frequency region of the spectrum in an extended band into a plurality of bands. The processor also sets a limited band for each divided band in the current frame, when a difference between a first frequency with a first maximum amplitude in a spectrum of the divided band in a preceding frame and a second frequency with a second maximum amplitude in a spectrum of the divided band in a current frame is below a threshold. The processor further encodes the spectrum in the limited band within each divided band in the current frame, and does not encode a spectrum outside the limited band within each divided band in the current frame.
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Citations
12 Claims
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1. A speech/audio coding apparatus, comprising:
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a receiver that receives a time-domain speech input signal; a processor that transforms a time-domain speech input signal into a frequency-domain spectrum; divides a frequency region of the spectrum in an extended band into a plurality of bands; sets a limited band for each divided band in the current frame, when a difference between a first frequency with a first maximum amplitude in a spectrum of the divided band in a preceding frame and a second frequency with a second maximum amplitude in a spectrum of the divided band in a current frame is below a threshold, a width of the limited band in the current frame being narrower than the divided band and the limited band including the first frequency; and encodes the spectrum in the limited band within each divided band in the current frame, and does not encode a spectrum outside the limited band within each divided band in the current frame. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A speech/audio coding method, comprising:
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transforming a time-domain speech input signal into a frequency-domain spectrum; dividing a frequency region of the spectrum in an extended band into a plurality of bands; setting a limited band for each divided band in the current frame, when a difference between a first frequency with a first maximum amplitude in a spectrum of the divided band in a preceding frame and a second frequency with a second maximum amplitude in a spectrum of the divided band in a current frame is below a threshold, a width of the limited band in the current frame being narrower than the divided band, and the limited band including the first frequency; and encoding the spectrum in the limited band within each divided band in the current frame, and not encoding a spectrum outside the limited band within each divided band in the current frame. - View Dependent Claims (8, 9, 10, 11, 12)
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Specification