APPARATUS AND METHOD FOR GENERATING A BANDWIDTH EXTENDED SIGNAL FROM A BANDWIDTH LIMITED AUDIO SIGNAL

摘要

An apparatus (100) for generating a bandwidth extended signal (135) from a bandwidth limited audio signal (105), the bandwidth limited audio signal (105) comprising a plurality of consecutive bandwidth limited time blocks (511), each bandwidth limited time block having at least one associated spectral band replication parameter comprising a core frequency band and the bandwidth extended signal (135) comprising a plurality of consecutive bandwidth extended time blocks (513), comprises a patch generator (110), a signal manipulator (120) and a combiner (130). The patch generator (110) is configured for generating a patched signal (115) comprising an upper frequency band using a bandwidth limited time block of the bandwidth limited audio signal (105). The patch generator (110) is configured to perform a harmonic patching algorithm (515) to obtain the patched signal (115). The patch generator (110) is configured to perform the harmonic patching algorithm (515) for a current bandwidth extended time block (m') of the plurality of consecutive bandwidth extended time blocks (513) using a timely preceding bandwidth limited time block (m - 1) of the plurality of consecutive bandwidth limited time blocks (511) of the bandwidth limited audio signal (105). The signal manipulator (120) is configured for manipulating a signal (105) before patching or the patched signal (115) generated using the timely preceding bandwidth limited time block (m - 1) using a spectral band replication parameter (121) associated with a current bandwidth limited time block (m) to obtain a manipulated patched signal (125) comprising the upper frequency band. The timely preceding bandwidth limited time block (m - 1) timely precedes the current bandwidth limited time block (m) in the plurality of consecutive bandwidth limited time blocks (511) of the bandwidth limited audio signal (105). The combiner (130) is configured for combining the bandwidth limited audio signal (105) comprising the core frequency band and the manipulated patched signal (125) comprising the upper frequency band to obtain the bandwidth extended signal (135).