Patent ID: 7050972
Filing Date: 2006-05-23
Classification: G10L

Abstract:
1. An apparatus for encoding an audio signal to obtain an encoded audio signal to be used by a decoder having a high-frequency reconstruction module for performing a high-frequency reconstruction for a frequency range above a crossover frequency, the apparatus comprising: a core encoder for encoding a lower frequency band of the audio signal up to the crossover frequency, the core encoder having a variable crossover frequency being controllable with respect to the variable crossover frequency, and operable on a block-wise frame by frame basis; and a crossover frequency control module for estimating, dependent on at least one of a measure of the degree of difficulty for encoding the audio signal by the core encoder and a border between a tonal and a noise-like frequency range of the audio signal, the crossover frequency to be selected by the core encoder for a frame of a series of subsequent frames, so that the crossover frequency is variable adaptively over time for the series of subsequent frames, the crossover frequency control module being adapted to control the core encoder with respect to the crossover frequency.