SOFA conventions

SOFA conventions specify the description of data and metadata for a particular kind of measured data.

This is important in order to meet the different requirements coming from different application fields, specified. For example, description of HRTFs, BRIRs, and DRIRs requires different metadata. Also, some applications may prefer to see the data stored in a different way. These conventions, once approved by the peer group are defined in SOFA conventions.

Stable SOFA Conventions

Stable SOFA conventions are those for which SOFA files are publicly available and can be read/modified by a software package. The following stable SOFA conventions are available now:

• GeneralFIR: General convention with FIR as DataType (no restrictions but DataType)
• GeneralTF: General convention with TF as DataType (no restrictions but DataType)
• SimpleFreeFieldHRIR: Free-field HRTFs stored as impulse responses, measured with an omnidirectional source for a single listener.
• SimpleHeadphoneIR: Conventions to store headphone IRs recorded for each emitter and each ear, single listener and no directionality of emitter/receiver considered.

Proposed SOFA Conventions

Proposed SOFA conventions are currently being discussed. We consider following rules for new SOFA conventions:

• Data must exist (do not foresee the future)
• Data can not be described by existing SOFA conventions
• Relevant information about the data available

The following SOFA conventions are being discussed. Measured data exist but their description must be fixed in order to create publicly available SOFA files and corresponding software interfaces.

• SimpleFreeFieldTF: as SimpleFreeFieldHRIR, but uses TF as DataType covering special needs coming from HRTF simulations
• SingleRoomDRIR: Room impulse responses measured with an arbitrary number of receivers (such as a microphone array) and an omnidirectional source in a single room.
• SimpleFreeFieldSOS: as SimpleFreeFieldHRIR, but uses SOS as DataType (second-order sections) covering special needs coming from HRTF rendering

• (SimpleBRIR): Binaural room impulse responses measured with an omnidirectional source in a single reverberant space. Somebody wanted to have this, but the work stopped at the moment.

Unsorted topics

Here we list the suggestions and feedback from the peer group:

• Include anthropometric data
• Crosstalk cancellation filters
• Include calibration data from the measurement
• Include room pictures

Please use the "Discussion" function to discuss these topics.

Feedback and Contribution

If you would like to contribute or propose new SOFA conventions:

• Send an e-mail to the mailing list. You don't have to be a member of the mailing list to send a message to the moderator.
• Go to one of the SOFA pages of your interest and use the "Discussion" for your contribution.

We appreciate your feedback!