Improvement to ATRAC encoder to reduce quantization noise.
Abstract
A method for enhancing a block companding uniform midtread quantizer in the ATRAC (Adaptive Transform Acoustic Coding) for the quantization of digital audio signals, wherein the audio signals are represented by a plurality of frames of quantized spectral components. The method includes modifying all spectral sample values in a defined frequency interval by a constant factor, calculating a scale factor for the frequency interval from a maximum spectral sample value, and quantizing all the spectral samples in the modified frequency interval with a modified quantizer.