Patent ID: 9037454
Filing Date: 2015-05-19
Classification: G10L

Abstract:
1. A system for encoding an audio signal, comprising: a device for processing an input audio signal using a modulated complex lapped transforms (MCLT) to produce blocks of transform coefficients for the audio signal; a device for transforming the MCLT coefficients to a magnitude-phase representation via a rectangular to polar conversion; a device for scaling the MCLT coefficients using a scaling factor; a device for quantizing the magnitude and phase of the scaled MCLT coefficients into quantization bins using polar quantization; wherein separate bit rates are selected for each scaled MCLT coefficient from a set of predefined bit rates for quantizing the phase of each scaled MCLT coefficient, with each selected bit rate corresponding to a particular pre-defined range of magnitudes of the scaled MCLT coefficients; and a device for encoding the quantized magnitude and phase of the scaled MCLT coefficients to create an entropy encoded version of the input audio signal, wherein a rate-distortion level of the encoded version of the input audio signal is directly controlled by the scaling factor as a result of the bit rates selected for quantizing the phase of each scaled MCLT coefficient, and wherein the scaling factor is included in the encoded version of the input audio signal.