The data is based on the KEMAR HRTF data provided by MIT, which can be found at
<http://sound.media.mit.edu/resources/KEMAR.html>. The compact measurements
were used. See hrtf_tables.inc for more information.
The filter is only available for stereo output, using a 44100hz playback rate.
Note also that it currently only applies to mono sounds, and the cf_level and
head_dampen config options are ignored while it is active.
All previous versions of the library treated the source cone angles as half
angles, which is contrary to the spec. Setting the __ALSOFT_HALF_ANGLE_CONES
environment variable to "true" or "1" restores the buggy behavior for
compatibility with applications that expect it.
This is not a config file option because new apps should not be made to depend
on the old behavior.
The spec intends the property values to be the full angle encompassed by the
cones, but the calculation interprets them as the angle from the center
point.
Mono sources and effects already output according to the available output
device channels. Multiplying the device matrix with the source matrix results
in a matrix that has the same effect as applying the source matrix followed by
the device matrix, so all the channel remixing can be done in one place.
Currently it behaves just like a normal device except contexts are only
processed during calls to alcRenderSamples. Additionally, the ALC_SYNC and
ALC_REFRESH context attributes are not valid for these devices, and there are
two new context attributes to specify the rendering format: ALC_FORMAT_TYPE
and ALC_FORMAT_CHANNELS. These each take one of the type and channel enums
added.
This stuff is subject to change.
