1. A method for arithmetic decoding of a current spectral coefficient using preceding spectral coefficients, said preceding spectral coefficients are already decoded, and both, said preceding and current spectral coefficients are comprised in one or more quantised spectra resulting from quantising time-frequency-transform of video, audio or speech signal sample values, said method comprising using processing means for processing the preceding spectral coefficients; using the processed preceding spectral coefficients for determining a context class being one of at least two different context classes, wherein a sum of the quantised absolutes of the preceding spectral coefficients is used for determination of the context class; using the determined context class and a mapping from the at least two different context classes to at least two different probability density functions for determining the probability density function; and arithmetic decoding the current spectral coefficient based on the determined probability density function, wherein processing the preceding spectral coefficients comprises non-uniformly quantising absolutes of the preceding spectral coefficients for use in determination of the context class.