We propose a hybrid warped linear prediction (WLP) AAC audio coding algorithm. The proposed algorithm employs a warped linear prediction processor to construct a perceptual pre and post-filter for the MPEG-4 AAC. The WLP residue is applied to the MDCT filter-bank and the signal to mask ratio of the corresponding block is modified to set a masking threshold for the WLP residues. In the decoder, the reconstructed residual signal is through a modified WLP synthesis filter to restore the audio signal. Subjective tests show that the proposed audio codec operating at 50kbps has comparable perceptual quality to the conventional MPEG-4 AAC operating at the 58kbps.
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