REPORT motlicek:rr07-43/IDIAP Non-uniform QMF Decomposition for Wide-band Audio Coding based on Frequency Domain Linear Prediction Motlicek, Petr Ganapathy, Sriram Hermansky, Hynek Garudadri, Harinath EXTERNAL http://publications.idiap.ch/attachments/reports/2007/motlicek-idiap-rr-07-43.pdf PUBLIC Idiap-RR-43-2007 2007 IDIAP This paper presents a new technique for perfect reconstruction non-uniform QMF decomposition developed to increase efficiency of a generic wide-band audio coding system based on Frequency Domain Linear Prediction (FDLP). The base line FDLP codec, operating at high bit-rates (~136 kbps,',','), exploits an uniform QMF decomposition into 64 sub-bands followed by sub-band processing based on FDLP. Here, we propose a non-uniform QMF decomposition into 32 frequency sub-bands obtained by merging 64 uniform QMF bands. The merging operation is performed in such a way that bandwidths of the resulting critically sampled sub-bands emulate the characteristics of the critical band filters in the human auditory system. Such frequency decomposition, when employed in the FDLP audio codec, results in a bit-rate reduction of 40% over the base line. We also describe the complete audio codec, which provides high-fidelity audio compression at ~66 kbps. In subjective listening tests, the FDLP codec outperforms MPEG-1 Layer 3 (MP3) and achieves similar qualities as MPEG-4 AAC+ standard.