AUDIO ENCODING DEVICE AND AUDIO ENCODING METHOD

摘要

It is possible to reduce audio quality degradation caused by a pre-echo and bit shortage. An acoustic analysis unit (11) analyzes an audio signal and acquires a perception entropy as a parameter expressing the number of bits required for quantization. An encoding bit quantity monitoring unit (12) monitors the number of encoded bits when an audio signal is encoded and acquires an excessive number of bits as the number of bits which can be used in the current frame. According to a combination of the perception entropy and the excessive number of bits, a frame division quantity decision unit (13) decides the division quantity for dividing the one frame of the audio signal into N from 1 to N. An orthogonal conversion unit (14) divides the one frame by the decided division quantity and performs orthogonal conversion of the audio signal by the divided block length unit so as to obtain an orthogonal conversion coefficient. A quantization unit (15) quantizes the orthogonal conversion coefficient by the block length unit.