Patent ID: 11942101
Assignee: FRAUNHOFER GESELLSCHAFT ZUR FÖRDERUNG DER ANGEWANDTEN FORSCHUNG E.V.
Field: Basic communication processes (Electrical engineering)
Classification: CPC G  H | IPC G  H

Claim 4:
5. Method for encoding a sequence of segments of coefficients, the segments being subsequent to each other in time, the method comprising providing the sequence of segments of coefficients from an audio stream representing a sampled audio signal by using different transform lengths such that segments of coefficients for which different transform lengths are used, spectrally represent the sampled audio signal at different frequency resolutions;
deriving, using a computer, a coding context for a currently encoded coefficient of a current segment based on a previously encoded coefficient of a previous segment, the previous and current segments corresponding to different frequency resolutions and different transform lengths, respectively; and
entropy encoding, using the computer, using arithmetic coding, the current coefficient based on the coding context to acquire an encoded audio stream,
wherein the entropy encoding comprises encoding the current coefficient in units of a tuple of spectral coefficients and for predicting a range of the tuple based on the coding context, and
wherein the entropy encoding comprises dividing the tuple by a predetermined factor as often as necessitated to fit a result of the division in a predetermined range and for encoding a number of divisions necessitated, a division remainder and the result of the division when the tuple does not lie in the predicted range, and encoding the tuple without the use of any division when the tuple already lies within the predicted range.