Speech encoding apparatus and speech encoding method

Abstract

There is provided an audio encoding device capable of maintaining continuity of spectrum energy and preventing degradation of audio quality even when a spectrum of a low range of an audio signal is copied at a high range a plurality of times. The audio encoding device (100) includes: an LPC quantization unit (102) for quantizing an LPC coefficient; an LPC decoding unit (103) for decoding the quantized LPC coefficient; an inverse filter unit (104) for flattening the spectrum of the input audio signal by the inverse filter configured by using the decoding LPC coefficient; a frequency region conversion unit (105) for frequency-analyzing the flattened spectrum; a first layer encoding unit (106) for encoding the low range of the flattened spectrum to generate first layer encoded data; a first layer decoding unit (107) for decoding the first layer encoded data to generate a first layer decoded spectrum, and a second layer encoding unit (108) for encoding.

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