APPARATUS AND METHOD FOR CENTER SIGNAL SCALING AND STEREOPHONIC ENHANCEMENT BASED ON A SIGNAL-TO-DOWNMIX RATIO

摘要

An apparatus for generating a modified audio signal having two or more modified audio channels from an audio input signal comprising two or more audio input channels is provided. The apparatus has an information generator for generating signal-to-downmix information. The information generator is adapted to generate signal information by combining a spectral value of each of the two or more audio input channels in a first way. The information generator is adapted to generate downmix information by combining the spectral value of each of the two or more audio input channels in a second way being different from the first way. Furthermore, the information generator is adapted to combine the signal information and the downmix information to obtain signal-to-downmix information. The apparatus has a signal attenuator for attenuating the two or more audio input channels depending on the signal-to-downmix information to obtain the two or more modified audio channels.

主权项

1. An apparatus for generating a modified audio signal comprising two or more modified audio channels from an audio input signal comprising two or more audio input channels, wherein the apparatus comprises:
an information generator for generating signal-to-downmix information, wherein the information generator is adapted to generate signal information by combining a spectral value of each of the two or more audio input channels in a first way, wherein the information generator is adapted to generate downmix information by combining the spectral value of each of the two or more audio input channels in a second way being different from the first way, and wherein the information generator is adapted to combine the signal information and the downmix information to acquire signal-to-downmix information, and a signal attenuator for attenuating the two or more audio input channels depending on the signal-to-downmix information to acquire the two or more modified audio channels, wherein the information generator is configured to generate the signal information Φ1(m, k) according to the formula:
Φ1(m,k)=ε{WX(m,k)(WX(m,k))H}, wherein the information generator is configured to generate the downmix information Φ2(m, k) according to the formula:
Φ2(m,k)=ε{VX(m,k)(VX(m,k))H}, and wherein the information generator is configured to generate a signal-to-downmix ratio as the signal-to-downmix information Rg(m, k, β) according to the formula:Rg(m,k,β)=(tr{Φ1(m,k)β}tr{Φ2(m,k)β})12β-1 wherein X(m, k) indicates the audio input signal, wherein
X(m,k)=[X1(m,k) . . . XN(m,k)]T,wherein N indicates the number of audio input channels of the audio input signal,
wherein m indicates a time index, and wherein k indicates a frequency index, wherein X1(m, k) indicates the first audio input channel, wherein XN(m, k) indicates the N-th audio input channel, wherein V indicates a matrix or a vector, wherein W indicates a matrix or a vector, wherein H indicates the conjugate transpose of a matrix or a vector, wherein ε{•} is an expectation operation, wherein β is a real number with β>0, and wherein tr{ } is the trace of a matrix.