Coding of harmonic signals in transform-based audio codecs
AssigneeDTS, Inc.
InventorsElias Nemer, Zoran Fejzo
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Abstract
Systems and methods include audio encoders having improved coding of harmonic signals. The audio encoders can be implemented as transform-based codecs with frequency coefficients quantized using spectral weights. The frequency coefficients can be quantized by use of the generated spectral weights applied to the frequency coefficients prior to the quantization or by use of the generated spectral weights in computation of error within a vector quantization that performs the quantization. Additional apparatus, systems, and methods are disclosed.
Claims20
A system having an audio codec, the system comprising:
- an input to the audio encoder to receive an audio signal;
- one or more processors;
- a memory storage having instructions stored therein, the instructions executable by the one or more processors to cause the audio encoder to perform operations to:
- generate frequency coefficients corresponding to the audio signal;
- generate spectral weights to perceptually shape a vector quantizer error, the weights derived in a compromise between altering a spectrum of the audio signal and reducing artifacts caused by missing quantized coefficients corresponding to use of quantized coefficients without weights;
- quantize the frequency coefficients by use of the generated spectral weights applied to the frequency coefficients prior to the quantization or by use of the generated spectral weights in computation of error within a vector quantization that performs the quantization;
- pack the quantized frequency coefficients into a bitstream to provide an encoded bitstream;
- and
- output the encoded bitstream from the audio encoder, the encoded bitstream including components to produce a signal representative of the audio signal;
- and
- an audio decoder that decodes the encoded bitstream without using spectral weights such that spectral weights are only generated and used by the audio encoder.
A processor-implemented method comprising:
- generating frequency coefficients corresponding to an audio signal received at an input of an audio encoder;
- generating spectral weights to perceptually shape a vector quantizer error, the weights derived in a compromise between altering a spectrum of the audio signal and reducing artifacts caused by missing quantized coefficients corresponding to using quantized coefficients without weights;
- quantizing the frequency coefficients using the generated spectral weights applied to the frequency coefficients prior to quantizing or using the generated spectral weights in computation of error within a vector quantization performing the quantizing;
- packing the quantized frequency coefficients into a bitstream providing an encoded bitstream;
- outputting the encoded bitstream from the audio encoder, the encoded bitstream including components to produce a signal representative of the audio signal;
- and
- decoding the encoded bitstream without using spectral weights such that spectral weights are only generated and used by the audio encoder.
A machine-readable storage device comprising instructions, which when executed by a set of processors, cause a system to perform operations, the operations comprising operations to:
- generate frequency coefficients corresponding to an audio signal received at an input of an audio encoder;
- generate spectral weights to perceptually shape a vector quantizer error, the weights derived in a compromise between altering a spectrum of the audio signal and reducing artifacts caused by missing quantized coefficients corresponding to use of quantized coefficients without weights;
- quantize the frequency coefficients by use of the generated spectral weights applied to the frequency coefficients prior to the quantization or by use of the generated spectral weights in computation of error within a vector quantization that performs the quantization;
- pack the quantized frequency coefficients into a bitstream to provide an encoded bitstream;
- output the encoded bitstream from the audio encoder, the encoded bitstream including components to produce a signal representative of the audio signal;
- and
- decoding the encoded bitstream without using spectral weights such that spectral weights are only generated and used by the audio encoder.
Dependencies are inferred from the claim text.