Parametric Bit Allocation in a Perceptual Audio Coder
The psychoacoustically based bit allocation algorithm employed in the AC-3 multichannel audio coder is presented. This algorithm differs from previous schemes in that it combines advantages of both forward and backward adaptation. The parametric approach is based upon conveying only the essential psychoacoustic features to the decoder instead of the entire bit assignment. The technique allows a greater percentage of the bits available for coding to be applied to audio data, and enables encoder improvements without modifying the decoder.
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