Fuchs, G.G.FuchsSubbaraman, V.V.SubbaramanRettelbach, N.N.RettelbachMultrus, M.M.MultrusGayer, M.M.GayerWarmbold, P.P.WarmboldGriebel, C.C.GriebelWeiss, O.O.Weiss2022-03-082022-03-082011https://publica.fraunhofer.de/handle/publica/309508An audio decoder (200) for providing a decoded audio information (212) on the basis of an encoded audio information (210) comprises a arithmetic decoder (230) for providing a plurality of decoded spectral values (232) on the basis of an arithmetically-encoded representation (222) of the spectral values and a frequency-domain-to-time-domain converter (260) for providing a time-domain audio representation (262) using the decoded spectral values, in order to obtain the decoded audio information. The arithmetic decoder (230) is configured to select a mapping rule describing a mapping of a code value onto a symbol code in dependence on a context state. The arithmetic decoder is configured to determine or modify the current context state in dependence on a plurality of previously-decoded spectral values. The arithmetic decoder is configured to detect a group of a plurality of previously-decoded spectral values, which fulfill, individually or taken together, a predetermined condition regarding their magnitudes, and to determine the current context state in dependence on a result of the detection. An audio encoder uses similar principles.en621006patent20090253459