Spatial Audio Processing: MPEG Surround and Other Applications

8.3 Binaural parameter analysis

8.3.1 Binaural parameters for a single sound source

In conventional binaural rendering systems, a sound source i with associated time-domain signal x_i(t) is rendered at a certain position by convolving the signal with a pair of headrelated impulse responses h_l,i(t), h_r,i(t), for the left and right ears, respectively, to result in binaural signals y_l,i(t), y_r,i(t):

with v ∈ {l, r}. This process is visualized in the left panel of Figure 8.1.

It is often convenient to express the convolution in the frequency domain using a frequency-domain representation X_i(f) of a short segment of x_i(t):

with H_l,i(f), H_r,i(f) the frequency-domain representations (head-related transfer functions) of h_l,i(t), h_r,i(t), respectively. The power p_yv,i at the eardrum resulting from signal y_v,i in frequency band b is given by:

Figure 8.1 Synthesis of a virtual sound source by means of HRIR convolution (left panel) and by means of parametric representations (right panel). Reproduced from Breebaart, J. (2007). Analysis and synthesis of binaural parameters for efficient 3D audio rendering in MPEG Surround. IEEE Int. Conf. on Multimedia and Expo (ICME 2007), Beijing, China. Copyright ...