Speech audio encoding device, speech audio decoding device, speech audio encoding method, and speech audio decoding method
First Claim
1. A speech/audio decoding apparatus, comprising:
- a receiver that receives encoded speech/audio data, including a limited-band mode flag;
a memory that stores information on a position of a maximum amplitude speech/audio spectrum frequency of a previous frame in a divided band; and
a processor thatidentifies whether a decoding band is encoded using a limited-band mode based on the decoded limited-band mode flag,wherein the limited-band mode is set at an encoder side, when a difference between a first frequency with a first maximum amplitude in a speech/audio spectrum of the divided band in a preceding frame and a second frequency with a second maximum amplitude in a speech/audio spectrum of the divided band in a current frame is below a threshold, a width of a limited band in the current frame being narrower than the divided band and the limited band including the first frequency, anddecodes the speech/audio spectrum in the limited band within each of the divided bands in the current frame using the stored information on the position of a maximum amplitude speech/audio spectrum frequency of the previous frame, when the decoding band is identified as the band encoded using the limited-band mode.
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Abstract
A speech/audio decoding apparatus is provided that includes a receiver that receives encoded data including a limited-band mode flag, and a memory that stores information on a position of a maximum amplitude spectrum frequency of a previous frame in a divided band. The speech/audio decoding apparatus also includes a processor that identifies whether a decoding band is encoded using a limited-band mode based on the decoded limited-band mode flag. Additionally, the processor decodes the spectrum in a limited band within each of the divided bands in a current frame using the stored information. Furthermore, the limited-band mode is set at an encoder side, 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 the current frame is below a threshold.
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Citations
8 Claims
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1. A speech/audio decoding apparatus, comprising:
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a receiver that receives encoded speech/audio data, including a limited-band mode flag; a memory that stores information on a position of a maximum amplitude speech/audio spectrum frequency of a previous frame in a divided band; and a processor that identifies whether a decoding band is encoded using a limited-band mode based on the decoded limited-band mode flag, wherein the limited-band mode is set at an encoder side, when a difference between a first frequency with a first maximum amplitude in a speech/audio spectrum of the divided band in a preceding frame and a second frequency with a second maximum amplitude in a speech/audio spectrum of the divided band in a current frame is below a threshold, a width of a limited band in the current frame being narrower than the divided band and the limited band including the first frequency, and decodes the speech/audio spectrum in the limited band within each of the divided bands in the current frame using the stored information on the position of a maximum amplitude speech/audio spectrum frequency of the previous frame, when the decoding band is identified as the band encoded using the limited-band mode. - View Dependent Claims (2, 3, 4)
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5. A speech/audio decoding method, comprising:
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receiving, by a receiver, an encoded speech/audio data, including a limited-band mode flag; storing information in a memory on a position of a maximum amplitude speech/audio spectrum frequency of a previous frame in a divided band; identifying, by a processor, whether a decoding band is encoded using a limited-band mode based on the decoded limited-band mode flag, wherein the limited-band mode is set at an encoder side, when a difference between a first frequency with a first maximum amplitude in a speech/audio spectrum of the divided band in a preceding frame and a second frequency with a second maximum amplitude in a speech/audio spectrum of the divided band in a current frame is below a threshold, a width of a limited band in the current frame being narrower than the divided band and the limited band including the first frequency, and decoding, by the processor, the speech/audio spectrum in the limited band within each of the divided bands in the current frame using the stored information on the position of a maximum amplitude speech/audio spectrum frequency of the previous frame, when the decoding band is identified as the band encoded using the limited-band mode. - View Dependent Claims (6, 7, 8)
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Specification