Multirate systems and filter banks
Multirate systems and filter banks
A Tutorial on MPEG/Audio Compression
IEEE MultiMedia
Speech coding based on spectral dynamics
TSD'06 Proceedings of the 9th international conference on Text, Speech and Dialogue
Wide-band audio coding based on frequency-domain linear prediction
EURASIP Journal on Audio, Speech, and Music Processing - Special issue on scalable audio-content analysis
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This paper describes employment of non-uniform QMF decomposition to increase the 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 a 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 HE-AAC codec.