[Openal] <native device> and HRTFs

[Anish Chandak]

On 7/11/07, Katharina Garbe <katharina.garbe at fit.fraunhofer.de> wrote:
>
> 4. As an alternative: Is there anyone here who has implemented
> HRTF-functionality on their own? Something like doing convolution in
> real-time in software?
>

Following are the general steps I followed to implement HRTFs based 3D
audio in software.

1) Get HRTF data from somewhere (MIT Kemar dummy or
http://interface.cipic.ucdavis.edu/index.htm)

[Assuming that you have a simple application where you want to play
one source and give it 3D spatialization effect using HRTFs. Give more
details on your application and I will answer back.]
[I used FMOD audio libray so the details for OpenAL might vary slightly]

2) Audio data refers to the audio associated with the sound source.
3) Create two 2D sound sources (one for left ear and one for the
right, by using panning).
4) Use filters for left and right ear to modify the audio data for
left and right ear (I used Intel Math Kernel Libray for convolution).
5) Then play this audio data (using the two sound sources you created earlier).

I do not think that openAL has any support for callback function so
you before you play your audio data you will have to do the
convolution.

> 3. Is HRTF-functionality = = EAX 5.0?
>

EAX 5.0 supports 3D sound and hell lot of other effects but I am
guessing that it is not synonymous with 3D sound using HRTFs.

Anish