SimpleFreeFieldSOS
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Description
This SOFA convention set is similar to SimpleFreeFieldHRIR. The only difference is the DataType, which is SOS, not FIR. SimpleFreeFieldSOS was requested to cover the needs coming from fast HRTF rendering, where an HRTF is represented as a broadband delay and small number of second-order sections (SOSs).
It is recommended to use SimpleFreeFieldHRSOS instead, which is defined in AES69-2020 (SOFA 2.0).
Version 1.0
This version follows the conventions SimpleFreeFieldHRIR (version 1.0) standardized in AES69-2015.
Note:
- In contrast to SimpleFreeFieldHRIR 1.0, SimpleFreeFieldSOS 1.0 has not been included in the standard. But it can be considered as stable.
- SimpleFreeFieldSOS does not impose any restriction on the filter coefficients contained in Data.SOS. Especially it is the user responsibility to check whether the filters are stable or not.
- We encourage to provide information in 'History' about the creation of SOSs and estimation of delay from the underlying filters.
- We further encourage to use 'Parents' can be used to link the SimpleFreeFieldSOS file with the file containing the original filters.
| Name | Default | Flags | Dimensions | Type | Comment |
|---|---|---|---|---|---|
| GLOBAL:Conventions | SOFA | rm | attribute | ||
| GLOBAL:Version | 1.0 | rm | attribute | ||
| GLOBAL:SOFAConventions | SimpleFreeFieldSOS | rm | attribute | This convention set follows SimpleFreeFieldHRIR but the data is stored as second-order section (SOS) coefficients. | |
| GLOBAL:SOFAConventionsVersion | 1.0 | rm | attribute | ||
| GLOBAL:APIName | rm | attribute | |||
| GLOBAL:APIVersion | rm | attribute | |||
| GLOBAL:ApplicationName | attribute | ||||
| GLOBAL:ApplicationVersion | attribute | ||||
| GLOBAL:AuthorContact | m | attribute | |||
| GLOBAL:Comment | attribute | ||||
| GLOBAL:DataType | SOS | rm | attribute | Filters described as second-order section (SOS) coefficients | |
| GLOBAL:History | attribute | ||||
| GLOBAL:License | No license provided, ask the author for permission | m | attribute | ||
| GLOBAL:Organization | m | attribute | |||
| GLOBAL:References | attribute | ||||
| GLOBAL:RoomType | free field | m | attribute | ||
| GLOBAL:Origin | attribute | ||||
| GLOBAL:DateCreated | m | attribute | |||
| GLOBAL:DateModified | m | attribute | |||
| GLOBAL:Title | m | attribute | |||
| ListenerPosition | [0 0 0] | m | IC, MC | double | |
| ListenerPosition:Type | cartesian | m | attribute | ||
| ListenerPosition:Units | metre | m | attribute | ||
| ReceiverPosition | [0 0.09 0; 0 -0.09 0] | m | rCI, rCM | double | |
| ReceiverPosition:Type | cartesian | m | attribute | ||
| ReceiverPosition:Units | metre | m | attribute | ||
| SourcePosition | [0 0 1] | m | IC, MC | double | Source position is assumed to vary for different directions/positions around the listener |
| SourcePosition:Type | spherical | m | attribute | ||
| SourcePosition:Units | degree, degree, metre | m | attribute | ||
| EmitterPosition | [0 0 0] | m | eCI, eCM | double | |
| EmitterPosition:Type | cartesian | m | attribute | ||
| EmitterPosition:Units | metre | m | attribute | ||
| GLOBAL:DatabaseName | m | attribute | name of the database to which these data belong | ||
| GLOBAL:ListenerShortName | m | attribute | ID of the subject from the database | ||
| ListenerUp | [0 0 1] | m | IC, MC | double | |
| ListenerView | [1 0 0] | m | IC, MC | double | |
| ListenerView:Type | cartesian | m | attribute | ||
| ListenerView:Units | metre | m | attribute | ||
| Data.SOS | permute([0 0 0 1 0 0; 0 0 0 1 0 0], [3 1 2]); | m | mRn | double | Filter coefficients as SOS coefficients. |
| Data.SamplingRate | 48000 | m | I | double | Sampling rate of the coefficients in Data.SOS and the delay in Data.Delay |
| Data.SamplingRate:Units | hertz | m | attribute | ||
| Data.Delay | [0 0] | m | IR, MR | double | Broadband delay (in samples resulting from SamplingRate) |