The D5 lattice quantization for 64 kbit/s low-delay subband audio coder with a 15 kHz bandwidth

A new method for coding generic audio signals at 64 kbit/s in the 20-15000 Hz bandwidth with a low delay is presented. It combines subband coding, low delay CELP algorithm and cascaded filterbanks. Our earlier works (1996) show that, when using an equal bit rate on each subband, the resulting audio quality was not appropriate. We propose a new technique based on lattice quantization to avoid the search complexity of the statistical vector quantization. It allows an adaptive bit rate allocation in each subband. Experimental results assessing the validity of the proposed method are also presented