CPC G10L 19/087 (2013.01) [G10L 19/06 (2013.01); G10L 19/16 (2013.01); G10L 19/26 (2013.01); G10L 19/265 (2013.01); G10L 19/0212 (2013.01); G10L 19/08 (2013.01)] | 26 Claims |
1. An audio encoder for encoding a non-speech audio signal so as to produce therefrom a bitstream, the audio encoder comprising:
a combination of a linear predictive coding filter comprising a plurality of linear predictive coding coefficients and a time-frequency converter, wherein the combination is configured to filter and to convert a frame of the audio signal into a frequency domain in order to output a spectrum based on the frame and on the linear predictive coding coefficients;
a low frequency emphasizer configured to calculate a processed spectrum based on the spectrum, wherein spectral lines of the processed spectrum representing frequencies lower than a reference spectral line are emphasized;
a control device configured to control the calculation of the processed spectrum by the low frequency emphasizer depending on the linear predictive coding coefficients of the linear predictive coding filter;
a quantization device configured to produce a quantized spectrum based on the processed spectrum;
and a bitstream producer configured to embed the quantized spectrum and the linear predictive coding coefficients into the bitstream;
wherein the control device comprises a spectral analyzer configured to estimate a spectral representation of the linear predictive coding coefficients and a minimum-maximum analyzer configured to estimate a minimum of the spectral representation below a further reference spectral line and a maximum of the spectral representation below the further reference spectral line;
wherein the control device is configured in such a way that the spectral lines of the processed spectrum representing frequencies lower than the reference spectral line are emphasized only if the maximum is less than the minimum multiplied with a first preset value.
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