Method and apparatus for split-band encoding and split-band decoding of audio information using adaptive bit allocation to adjacent subbands
First Claim
1. An encoder for the high-quality digital encoding of wideband audio information, comprisingsubband means for receiving said wideband audio information and for generating subband information for a plurality of subbands in response thereto,quantizing means for forming digital words by adaptively allocating bits to and quantizing said subband information, wherein bits are adaptively allocated to digital words representing a respective subband and one or two adjacent subbands on the basis of a spectral level in said respective subband, andformatting means for assembling digital information including said digital words into a coded signal having a format suitable for transmission or storage.
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Abstract
A split-band encoder and a split-band decoder use adaptive bit allocation to achieve high-quality audio coding at low bit rates. Bits are adaptively allocated to one or two subbands adjacent to a given subband based on signal levels in the given subband.
84 Citations
19 Claims
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1. An encoder for the high-quality digital encoding of wideband audio information, comprising
subband means for receiving said wideband audio information and for generating subband information for a plurality of subbands in response thereto, quantizing means for forming digital words by adaptively allocating bits to and quantizing said subband information, wherein bits are adaptively allocated to digital words representing a respective subband and one or two adjacent subbands on the basis of a spectral level in said respective subband, and formatting means for assembling digital information including said digital words into a coded signal having a format suitable for transmission or storage.
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7. A decoder for the high-quality reproduction of wideband audio information from a coded signal comprising digital words representing subband information for a plurality of subbands of said wideband audio information, said decoder comprising
deformatting means for receiving said coded signal and for deriving said digital words therefrom, linearization means for generating said subband information by adaptively allocating bits to and dequantizing said digital words, wherein bits are adaptively allocated to digital words representing a respective subband and one or two adjacent subbands on the basis of a spectral level in said respective subband, and inverse subband means for generating a representation of said wideband audio information in response to said subband information.
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16. A system for the high quality processing of wideband audio information including an encoder and a decoder, said encoder comprising
subband means for receiving said wideband audio information and for generating first subband information for a plurality of subbands in response thereto, quantizing means for forming digital words by adaptively allocating bits to and quantizing said first subband information, wherein bits are adaptively allocated to digital words representing a respective subband and one or two adjacent subbands on the basis of a spectral level in said respective subband, and formatting means for assembling digital information including said digital words into a coded signal having a format suitable for transmission or storage, and said decoder comprising deformatting means for receiving said coded signal and for deriving said digital words therefrom, linearization means for generating second subband information by adaptively allocating bits to and dequantizing said digital words, and inverse subband means for generating a representation of said wideband audio information in response to said second subband information.
Specification