|Methods and apparatus for gain controlling waveform elements ahead of an attack portion and waveform elements of a release portion
|Oct. 26, 1999/ Feb. 21, 1996
|Hatanaka; Mitsuyuki, Oikawa; Yoshiaki, Tsutsui; Kyoya
|ATRAC2/3 Gain Control.
|A signal encoding method and apparatus for encoding input digital signals by so-called high efficiency encoding, and a recording medium having the encoded signals. An attack portion and a release portion of audio signals are detected and a gain control function is selected at least for waveform elements (waveform signals) of a signal portion ahead of the attack portion and waveform elements of the release portion from among plural gain control functions responsive to characteristics of the waveform signals. At least the waveform elements (waveform signals) ahead of the attack portion and the waveform elements of the release portion are gain controlled. The resulting gain-controlled audio signals are transformed into plural spectral components which are encoded along with the control information for gain control. With the present encoding method and apparatus, the encoding efficiency may be improved, while pre-echo and post-echo may be effectively prohibited and the sound quality may be prohibited from being deteriorated even for the high compression ratio.