A quantization method of direct noise shaping and level matching for the low complexity implementation of MPEG-4 AAC encoder

This work presents a new structure of MPEG-4 AAC encoder. The proposed encoder directly shapes quantization noise distribution according to the energy distribution and thereafter performs adjustment of the offset level of the noise distribution to meet the target bit rate. The direct noise shaping and the bit rate matching scheme significantly alleviate the problem of processing burden of the conventional encoder related with the precise modeling of the psychoacoustics and iteration intensive quantization.