Spatial Audio Processing: MPEG Surround and Other Applications

8.4 Binaural parameter synthesis

8.4.1 Mono down-mix

The synthesis process comprises reinstating the binaural parameters on a mono down-mix signal x(t) of the object signals. Using a frequency-domain representation, one frame of the down-mix signal is given by:

The power in each band of this down-mix signal frame, p_x, is then given by:

The reconstructed binaural signals Ŷ_t Ŷ_r are obtained using a matrix operation W_b that is derived for each parameter band (b) independently:

with D(.) a decorrelator which generates a signal that has virtually the same temporal and spectral envelopes as its input, but is independent of its input. The matrix coefficients ensure that for each frame, the two binaural output signals Ŷ_t Ŷ_r have the desired levels, IPD and IC relations. The solution for W_b is given by (see Chapter 5 for a detailed explanation of these equations):

with

8.4.2 Extension towards ...