Patent ID: 8571876

Claim:
An apparatus for acquiring one or more model parameters describing a variation of a signal characteristic of an audio signal on the basis of actual transform domain parameters of a transform domain representation of the signal describing the signal in a transform domain, the apparatus comprising: a parameter determinator configured to determine one or more model parameters of a transform-domain variation model, the variation model describing an evolution of transform domain parameters in dependence on the one or more model parameters, such that a model error, representing a deviation between a modelled evolution of the transform domain parameters and an evolution of the actual transform domain parameters, is brought below a predetermined threshold value or minimized; wherein the apparatus is configured to acquire, as the actual transform-domain parameters, first transform domain information which comprises a first set of transform domain parameters and describes the audio signal for a first time interval for a plurality of different values of the transform variable, and second transform domain information describing the audio signal for a second time interval for the different values of the transform variable; wherein the parameter determinator is configured to evaluate, for a plurality of different values of the transform variable, a temporal variation between the first transform domain information and the second transform domain information, to acquire temporal variation information, to estimate a local variation of the transform domain information over the transform variable for a plurality of different values of the transform variable, to acquire a local variation information, and to combine the temporal variation information and the local variation information, to acquire a frequency variation model parameter; wherein the parameter determinator is configured to acquire the frequency variation model parameter using a transform domain variation model comprising the frequency variation model parameter and representing a compression or expansion of the transform domain representation of the audio signal with respect to the transform variable assuming a smooth frequency variation of the audio signal; wherein the parameter determinator is configured to determine the frequency variation model parameter such that the parameterized transform-domain variation model is adapted to the first set of transform domain parameters and the second set of transform domain parameters.