Audio processing method, audio processing apparatus, and non-transitory computer-readable storage medium for storing audio processing computer program

An audio processing apparatus comprising:

• a memory;
• and
• a processor coupled to the memory and configured to
• execute a delay amount acquisition process that includes acquiring, for each of a plurality of elapsed times, a delay amount of a second head-related transfer function relative to a first head-related transfer function, the first head-related transfer function indicating sound transfer characteristics in a head of a user for a first sound source direction, the second head-related transfer function indicating sound transfer characteristics in the head of the user for a second sound source direction, and
• execute an interpolation process that includes calculating, for each of the plurality of elapsed times, a value of a third head-related transfer function at the elapsed time, by interpolating a first value and a second value based on a first angular difference and a second angular difference, the third head-related transfer function indicating sound transfer characteristics in the head of the user for a third sound source direction, the a first value being a value of the first head-related transfer function at the elapsed time, the second value being a value of the second head-related transfer function at a time delayed from the elapsed time by a delay amount corresponding to the elapsed time, the first angular difference being an angular difference between the third sound source direction and the first sound source direction, the second angular difference being an angular difference between the third sound source direction and the second sound source direction.

A non-transitory computer-readable storage medium for storing a audio processing computer program, the audio processing computer program causing a processor to perform processing, the processing comprising:

• executing a delay amount acquisition process that includes acquiring, for each of a plurality of elapsed times, a delay amount of a second head-related transfer function relative to a first head-related transfer function, the first head-related transfer function indicating sound transfer characteristics in a head of a user for a first sound source direction, the second head-related transfer function indicating sound transfer characteristics in the head of the user for a second sound source direction;
• and
• executing an interpolation process that includes calculating, for each of the plurality of elapsed times, a value of a third head-related transfer function at the elapsed time, by interpolating a first value and a second value based on a first angular difference and a second angular difference, the third head-related transfer function indicating sound transfer characteristics in the head of the user for a third sound source direction, the a first value being a value of the first head-related transfer function at the elapsed time, the second value being a value of the second head-related transfer function at a time delayed from the elapsed time by a delay amount corresponding to the elapsed time, the first angular difference being an angular difference between the third sound source direction and the first sound source direction, the second angular difference being an angular difference between the third sound source direction and the second sound source direction.