Encoder apparatus, decoder apparatus and methods of these

摘要

There is disclosed an encoder apparatus whereby, when a band expanding technique for encoding, based on the spectral data of a lower frequency portion, the spectral data of a higher frequency portion is applied to a lower layer in a hierarchical encoding/decoding system, an efficient encoding can be performed in an upper layer as well, thereby improving the decoded-signal quality. In an encoder apparatus (101), a second layer decoder unit (207) calculates a spectrum (differential spectrum), which is to be encoded in a third layer encoder unit (210) that is an upper layer of the second layer decoder unit (207), by applying such an ideal gain (first gain parameter a1) that minimizes the energy of the differential spectrum.

主权项

1. A coding apparatus comprising:
a first coding section that inputs a low-frequency decoded signal of a frequency domain generated using low-frequency coded information obtained by encoding an input signal and the input signal of the frequency domain, generates a high-frequency decoded signal of the frequency domain using high-frequency coded information obtained through encoding using the low-frequency decoded signal and the input signal, generates a band extension signal using the low-frequency decoded signal and the high-frequency decoded signal and generates a difference signal between the input signal and the band extension signal; and a second coding section that encodes the difference signal to generate difference coded information, wherein: the first coding section searches a part approximate to the high-frequency part of the input signal from the low-frequency decoded signal in encoding using the low-frequency decoded signal and the input signal to thereby obtain an ideal gain that minimizes energy of the difference signal, generate the difference signal that minimizes the energy and generate the high-frequency coded information including the ideal gain.