Information encoding method and apparatus, information decoding method and apparatus information transmission method and information recording medium

摘要

An information encoding method and apparatus, an information decoding method and apparatus and an information transmission method in which encoding and decoding with higher efficiency and higher sound quality may be achieved by gain control in meeting with the degree of amplitude changes in the attack portion and the pre-echo may be prevented from occurring. Gain control and gain control compensation operations are performed by applying a gain control function with a smaller gain control quantity and by applying a gain control function with a larger gain control quantity to a signal waveform portion having a level just ahead of an attack portion higher than a pre-set level and to a signal waveform portion having an extremely low level just ahead of the attack portion, respectively. By changing the gain control quantity depending on the degree of amplitude changes at the attack portion of the signal waveform, the pre-echo is prevented from occurring, while the efficiency is prevented from being lowered due to energy diffusion in the frequency domain.