SOFA is a file format for reading, saving, and describing spatially oriented data of acoustic systems.
Examples of data we consider are head-related transfer functions (HRTFs), binaural room impulse responses (BRIRs), multichannel measurements such as done with microphone arrays, or directionality data of loudspeakers.
The format specifications are the major issue, but we also aim in providing APIs for reading and writing the data in SOFA.
For more information on the format specifications and available data have a look at http://www.sofaconventions.org/
Current versions of SOFA can be found on its old home.
At the moment we are working on a new release which will be shortly available on this site.
In order to use SOFA with Matlab or Octave you have to add its API_MO folder
to your paths. After that you can play around with your acoustic measurements
as shown by the following example which uses a head-related transfer function
measurement.
% Start SOFA
SOFAstart;
% Load your impulse response into a struct
hrtf = SOFAload('path/to_your/HRTF.sofa'));
% Display some information about the impulse response
SOFAinfo(hrtf);
% Plot a figure with the measurement setup
SOFAplotGeometry(hrtf);
% Have a look at the size of the data
size(hrtf.Data.IR)
% Get information about the measurement setup
hrtf.ListenerPosition % position of dummy head
hrtf.SourcePosition % position of loudspeaker
% Head orientation of the dummy head + coordinate system and units
hrtf.ListenerView
hrtf.ListenerView_Type
hrtf.ListenerView_Units
% Calculate the source position from a listener point of view
apparentSourceVector = SOFAcalculateAPV(hrtf);
% Listen to the HRTF with azimuth of -90°
apparentSourceVector(91, 1)
SOFAplotGeometry(hrtf, 91);
soundInput = audioread('fancy_audio_file.wav');
soundOutput = [conv(squeeze(hrtf.Data.IR(91, 1, :)), soundInput) ...
conv(squeeze(hrtf.Data.IR(91, 2, :)), soundInput)];
sound(soundOutput, hrtf.Data.SamplingRate);