A Multichannel Linear Prediction Method for the MPEG-4 ALS Compliant Encoder

A new linear prediction analysis method for multichannel signals was devised, with the goal of enhancing the compression performance of the MPEG-4 Audio Lossless coding (ALS) compliant encoder. The multichannel coding tool for this standard carries out an adaptively weighted subtraction of the residual signals of the coding channel from those of the reference channel, both of which are produced by independent linear prediction. Our linear prediction method tries to directly minimize the amplitude of the predicted residual signal after subtraction of the signals of the coding channel. The results of a comprehensive evaluation show that this method yields a 0.1% smaller compressed file size averagely, the maximum improvement of compression ratio achieves 14.6%, at the cost of a small increase in computational complexity at the encoder and without increase in decoding time. This is a practical method because the compressed bit stream remains compliant with the MPEG-4 ALS standard.