Patent ID: 6693963
Filing Date: 2004-02-17
Classification: G10L,H04B,H04N

Abstract:
A subband encoding apparatus comprising:a subband splitter dividing an input signal in a frequency band into subband signals; a first scale factor information producing circuit measuring signal levels of the subband signals to determine scale factors and producing scale factor information indicative thereof; a bit allocation information producing circuit producing bit allocation information based on the scale factor information; a second scale factor information producing circuit producing scale factor flag information indicating the fact that the scale factor information has changed from that one frame earlier and updated scale factor information indicating the scale factor information which has changed from that one frame earlier; a re-quantizing circuit re-quantizing the subband signals using the scale factor information and the bit allocation information to provide re-quantized output signals; a frame constructing circuit constructing a frame made up of the re-quantized signal, the updated scale factor information, and the scale factor flag information and outputs the frame as an encoded output signal; and a subband-limiting circuit limiting the number of subbands of the subband signals to be re-quantized by said re-quantizing circuit based on an upper limit frequency of an audible band.