Lecomte, J.J.LecomteNagel, F.F.NagelRobilliard, J.J.RobilliardGeiger, R.R.GeigerBorsum, A.A.BorsumFuchs, G.G.FuchsMultrus, M.M.Multrus2022-03-082022-03-082010https://publica.fraunhofer.de/handle/publica/309383An audio decoder comprises an arithmetic decoder for providing a plurality of decoded spectral values on the basis of an arithmetically-encoded representation of the spectral values and a frequency-domain to time-domain converter for providing a time-domain audio representation using the decoded spectral values, in order to obtain a decoded audio information. The arithmetic decoder is configured to derive a group index from a variable-length-codeword representing the group index in dependence on a state index. The arithmetic decoder is configured to derive the values of a most-significant bit-plane of a tuple of spectral values using the group index and an element index, and to provide a tuple of decoded spectral values using the values of the most-significant bit-plane of the tuple of spectral values. The arithmetic decoder is configured to select a cumulative-frequencies-table out of a set of 32 cumulative-frequencies-tables in dependence on the state index, and to apply the selected cumulative-frequencies-table to derive the group index from the variable-length codeword representing the group index.en621006patent20090147885