Patent ID: 9076438
Filing Date: 2015-07-07
Classification: G10L,H04B

Abstract:
1. An audio processing method comprising: (a) receiving a present time domain audio signal; (b) transforming the present time domain audio signal into a spectrum audio signal utilizing a modified discrete cosine transform (MDCT) algorithm, wherein the spectrum audio signal comprises a plurality of partition domains; (c) calculating a partitioned energy of each of the partition domains of the spectrum audio signal; (d) calculating a present spectral flatness measure (SFM) of the spectrum audio signal according to the spectrum audio signal; (e) obtaining a spreading function (SF) coefficient of each of the partition domains of the spectrum audio signal by referencing an SF table wherein the SF table is stored in a plurality of linear arrays, the linear arrays comprise a first linear array for storing an initial row address of the SF table of non-zero SF-coefficient values at each row, a second linear array for storing a terminal row address of the SF table of non-zero SF-coefficient values at each row, and a third linear array for storing the non-zero SF-coefficient values at each row of the SF table; (f) according to the partitioned energy of each of the partition domains of the spectrum audio signal, normalizing the corresponding SF coefficient for adjustment; (g) calculating a present tonality index according to the present SFM; (h) calculating a present signal-to-noise ratio (SNR) of each of the partition domains of the spectrum audio signal according to the present tonality index; (i) utilizing a logarithmic scale to calculate a masking partitioned energy threshold of each of the partition domains of the spectrum audio signal according to the present SNR and the adjusted SF coefficient of each of the partition domains of the spectrum audio signal; (j) obtaining an audio block type of each of the partition domains of the spectrum audio signal according to a present bandwidth, the partitioned energy and the masking partitioned energy threshold of each of the partition domains of the spectrum audio signal; (k) calculating a signal-to-mask ratio (SMR) of the spectrum audio signal according to the spectrum audio signal, the masking partitioned energy threshold of each of the partition domains of the spectrum audio signal and the present bandwidth; and (l) compressing the spectrum audio signal into an audio bit stream according to the audio block type of each of the partition domains of the spectrum audio signal and the SMR.