LINEAR PREDICTION BASED AUDIO CODING USING IMPROVED PROBABILITY DISTRIBUTION ESTIMATION

摘要

Linear prediction based audio coding is improved by coding a spectrum composed of a plurality of spectral components using a probability distribution estimation determined for each of the plurality of spectral components from linear prediction coefficient information. The linear prediction coefficient information is available anyway. Accordingly, it may be used for determining the probability distribution estimation at both encoding and decoding side. The latter determination may be implemented in a computationally simple manner by using, for example, an appropriate parameterization for the probability distribution estimation at the plurality of spectral components. The coding efficiency as provided by the entropy coding is compatible with probability distribution estimations as achieved using context selection, but its derivation is less complex. The derivation may be purely analytically and/or does not require any information on attributes of neighboring spectral lines such as previously coded/decoded spectral values of neighboring spectral lines as is the case in spatial context selection.

主权项

1. A linear prediction based audio decoder comprising:
a probability distribution estimator configured to determine, for each of a plurality of spectral components, a probability distribution estimation from linear prediction coefficient information comprised in a data stream into which an audio signal is encoded; an entropy decoding and dequantization stage configured to entropy decode and dequantize a spectrum composed of the plurality of spectral components from the data stream using the probability distribution estimation as determined for each of the plurality of spectral components; and a filter configured to shape the spectrum according to a transfer function depending on a linear prediction synthesis filter defined by the linear prediction coefficient information, wherein the probability distribution estimator is configured to determine a spectral fine structure from long-term prediction parameters comprised in the data stream and determine, for each of the plurality of spectral components, a probability distribution parameter such that the probability distribution parameters spectrally follow a function which multiplicatively depends on the spectral fine structure, wherein, for each of the plurality of spectral components, the probability distribution estimation is a parameterizable function parameterized with the probability distribution parameter of the respective spectral component.