Bandwidth expansion method and apparatus

A bandwidth expansion apparatus, comprising a processor, an estimation unit coupled to the processor, and a predictive decoding unit coupled to the processor;

• the estimation unit is configured to estimate a bandwidth of at least one previously decoded frame of a whole-band signal, so as to obtain an estimated bandwidth;
• wherein the estimated bandwidth is used as the estimated bandwidth of a current frame of a lower-band signal;
• and
• the predictive decoding unit is configured to perform bandwidth expansion for the lower-band signal by using different predictive decoding on the lower-band signal according to an effective bandwidth of the lower-band signal and the estimated bandwidth, comprising:
• a first predictive decoding sub-unit, configured to perform first predictive decoding on a part of the lower-band signal in a band above an effective bandwidth of the lower-band signal and below the estimated bandwidth, so as to obtain the part of the lower-band signal above the effective bandwidth of the lower-band signal and below the estimated bandwidth;
• and
• a second predictive decoding sub-unit, configured to perform second predictive decoding on a part of the lower-band signal in a band above the estimated bandwidth, so as to obtain the part of the lower-band signal above the estimated bandwidth.