Quantization noise suppression for encoder/decoder system
First Claim
1. An encoder of an input signal comprising signal samples, said encoder comprisingreceiver means for receiving said signal samples and for generating an auxiliary signal in response thereto, said auxiliary signal comprising subblocks of one or more samples,detector means for detecting transients within said auxiliary signal,selection means for generating side information indicating the position of one or more of said subblocks in proximity to one or more of said transients,filter bank means for generating subband information in response to said signal samples,quantizer means for generating quantized information by quantizing said subband information, andformatter means for assembling said quantized information and said side information into a form suitable for transmission or storage.
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Abstract
The invention relates in general to low bit-rate encoding and decoding of information such as audio information. More particularly, the invention relates to the suppression of quantizing noise which results from low bit-rate encoding and decoding of signal events such as transients. An encoder identifies intervals of an input signal in which a decoder is likely to generate audible artifacts caused by quantizing errors. Indications of these intervals are passed in the encoded signal to the decoder. The decoder uses these indications to eliminate quantizing artifacts by suppressing corresponding intervals in the output signal.
49 Citations
23 Claims
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1. An encoder of an input signal comprising signal samples, said encoder comprising
receiver means for receiving said signal samples and for generating an auxiliary signal in response thereto, said auxiliary signal comprising subblocks of one or more samples, detector means for detecting transients within said auxiliary signal, selection means for generating side information indicating the position of one or more of said subblocks in proximity to one or more of said transients, filter bank means for generating subband information in response to said signal samples, quantizer means for generating quantized information by quantizing said subband information, and formatter means for assembling said quantized information and said side information into a form suitable for transmission or storage.
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15. A decoder of encoded information representing an input signal, said decoder comprising
deformatter means for receiving said encoded signal and for extracting quantized information and side information therefrom, wherein said side information indicates one or more positions within said input signal, dequantizer means for dequantizing said quantized information into recovered subband information, inverse filter bank means for generating recovered signal samples in response to said recovered subband information, and suppressor means for generating an output signal in response to said recovered signal samples by suppressing selected ones of said recovered signal samples, said samples selected in response to said one or more positions indicated by said side information.
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22. An encoding method of an input signal comprising signal samples, said encoding method comprising
receiving said signal samples and generating an auxiliary signal in response thereto, said auxiliary signal comprising subblocks of one or more samples, detecting transients within said auxiliary signal, generating side information indicating the position of one or more of said subblocks in proximity to one or more of said transients, generating subband information in response to said signal samples, generating quantized information by quantizing said subband information, and assembling said quantized information and said side information into a form suitable for transmission or storage.
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23. A decoding method of encoded information representing an input signal, said decoding method comprising
receiving said encoded signal and extracting quantized information and side information therefrom, wherein said side information indicates one or more positions within said input signal, dequantizing said quantized information into recovered subband information, generating recovered signal samples in response to said recovered subband information, and generating an output signal in response to said recovered signal samples by suppressing selected ones of said recovered signal samples, said samples selected in response to said one or more positions indicated by said side information.
Specification