s1 |
Input signal |

s2 |
Input signal |

tau |
Lowpass filter parameter, such that a = exp(-1./(fs*tau)),
lowpass = filter([1-a], [1, -a], x) |

fc |
Center frequencies |

fs |
Sampling frequencies |

outp |
Structure containing the output. See the description below. |

XXX Description is missing. What does this function actually do?

**Note**: If *tau* is a scalar, lowpass is done on every channel
with the value of *tau*. If the filter parameter *tau* is a vector, it has
to have as many elements as the number of channels of *s1* and *s2*; each
value *tau(i)* is applied to the signals in `s1(i,:)` and `s2(i,:)`.

The output structure *outp* contains the following fields:

.itf |
Transfer function |

.itf_equal |
Transfer function without amplitude |

.ipd |
Phase difference in rad |

.ipd_lp |
Based on lowpass-filtered itf, phase difference in rad |

.ild |
Level difference in dB |

.itd |
Time difference based on instantaneous frequencies |

.itd_C |
Time difference based on central frequencies |

.itd_lp |
As .itd, with low-passed itf |

.itd_C_lp |
As .itd_C, with low-passed itf |

.f_inst_1 |
Instantaneous frequencies in the channels of the filtered s1 |

.f_inst_2 |
Instantaneous frequencies in the channels of the filtered s2 |

.f_inst |
Instantaneous frequencies (average of f_inst1 and f_inst_2) |

M. Dietz, S. D. Ewert, and V. Hohmann.
Auditory model based direction estimation of concurrent speakers from
binaural signals.
*Speech Communication*, 53(5):592-605, 2011.
[ DOI |
http ]