Patent ID: 7953604

Claim:
In an audio encoder, a computer-implemented method comprising: the audio encoder receiving source audio data; the audio encoder performing a time-to-frequency transform on the received source audio data to produce frequency-domain data for the received source audio data; the audio encoder partitioning the frequency-domain data into a plurality of sub-bands in a baseband frequency range and an extended-band frequency range; and the audio encoder performing frequency extension coding on the received source audio data, the frequency extension coding comprising determining one or more shape parameters for the frequency-domain data, wherein determining the one or more shape parameters comprises using a displacement vector that measures a displacement of a first sub-band in the extended-band frequency range relative to a second sub-band in the baseband frequency range; wherein the determining one or more shape parameters comprises for the first sub-band in the extended-band frequency range, finding the second sub-band in the baseband frequency range whose sub-band shape matches that of the first sub-band in the extended-band frequency range within a tolerance wherein said finding is restricted to sub-bands in the baseband frequency range that are only at a displacement of an even number of sub-bands from said first sub-band in the extended-band frequency range, and wherein the displacement measured by the displacement vector is an even number of sub-bands, wherein the sub-band shape matching is performed using a vector quantization process.