Information signal encoding using a forward-adaptive prediction and a backwards-adaptive quantization
AssigneeFraunhofer-Gesellschaft zur Foerderung der angewandten Forschung e.V.
InventorsJens Hirschfeld, Gerald Schuller, Manfred Lutzky, Ulrich Kraemer, Stefan Wabnik
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Abstract
A very coarse quantization exceeding the measure determined by the masking threshold without or only very little quality losses is enabled by quantizing not immediately the prefiltered signal, but a prediction error obtained by forward-adaptive prediction of the prefiltered signal. Due to the forward adaptivity, the quantizing error has no negative effect on the prediction on the decoder side.
Claims17
An apparatus for encoding an information signal into an encoded information signal, wherein the apparatus is configured to
- determine one or more first linear prediction coefficients so as to define a transfer function which approximates an inverse of a psycho-perceptibility motivated threshold;
- filter the information signal using the one or more first linear prediction coefficients, thereby attaining a prefiltered signal;
- determine one or more second linear prediction coefficients based on the prefiltered signal;
- predict the prefiltered signal using the one or more second linear prediction coefficients to attain a predicted signal and a prediction error for the prefiltered signal;
- quantize the prediction error for attaining a quantized prediction error,
- form, based on the quantized prediction error and the predicted signal, a reconstructed signal and perform the prediction of the prefiltered signal based on the reconstructed signal;
- and
- encode into the encoded information signal the one or more first linear prediction coefficients, the one or more second linear prediction coefficients and the quantized prediction error,
- wherein the information signal is an audio signal,
- wherein the apparatus comprises a computer.
A method for encoding an information signal into an encoded information signal, comprising:
- determine one or more first linear prediction coefficients so as to define a transfer function which approximates an inverse of a psycho-perceptibility motivated threshold;
- filtering the information signal using the one or more first linear prediction coefficients so as to attain a prefiltered signal;
- determining one or more second linear prediction coefficients based on the prefiltered signal;
- predicting the prefiltered signal using the one or more second linear prediction coefficients to attain a predicted signal and a prediction error for the prefiltered signal;
- quantizing the prediction error to attain a quantized prediction error;
- forming, based on the quantized prediction error and the predicted signal, a reconstructed signal and performing the prediction of the prefiltered signal based on the reconstructed signal;
- and
- encoding into the encoded information signal the one or more first linear prediction coefficients, the one or more second linear prediction coefficients and the quantized prediction error,
- wherein the information signal is an audio signal.
Dependencies are inferred from the claim text.