SimpleFreeFieldHRIR
Description
This conventions essentially defines the setup used in the ARI, LISTEN, FIU, CIPIC, and other similar HRTF databases. The measurements are done at a constant distance in free field with a single excitation source assuming an omnidirectional loudspeaker. Human listeners are considered and thus, the number of receivers is two. Azimuth and elevation angles are varied and the tilt of the head is not considered during the measurement. The measured HRTFs are represented as FIR filters, with a single HRTF set of a listener per file. The SOFA conventions SimpleFreeFieldHRIR defines such a setup. It requires: General attributes: SOFAConventions: SimpleFreeFieldHRIR, Datatype: FIR, RoomType: free field, other general attributes... Data: The number of receivers is two, thus, the size of Data.IR is [M 2 N]. Only a single sampling rate for the file is allowed, thus SamplingRate is a scalar. Source: Source is in the origin of the setup and consists of a single emitter. SourcePosition: (0 0 0), SourceUp: (0 0 1), SourceView: (1 0 0), SourceRotation, and EmitterPosition: (0 0 0).
- Listener: The listener is in the measurement distance X (in meter) from the source, facing the source. ListenerPosition: (X 0 0), ListenerView: (0 0 0), ListenerUp: (X 0 1).
- Receivers: Two receivers (=ears) on a head with radius H (in meter): ReceiverPosition: (0 -H 0; 0 +H 0).
- The different azimuth and elevation angles of the measurement are described by the ListenerRotation as [M 3] matrix (in degrees). The coordinate type is DIN 9300.
Proposed (for SOFA 0.4)
| Name | Default | Flags | Dimensions | Type | Comment |
|---|---|---|---|---|---|
| GLOBAL_Conventions | SOFA | rm | |||
| GLOBAL_Version | 0.3 | rm | |||
| GLOBAL_SOFAConventions | SimpleFreeFieldHRIR | rm | |||
| GLOBAL_SOFAConventionsVersion | 0.1 | rm | |||
| GLOBAL_APIName | rm | Insert the API Name here | |||
| GLOBAL_APIVersion | rm | Insert the API Version here | |||
| GLOBAL_ApplicationName | m | ||||
| GLOBAL_ApplicationVersion | m | ||||
| GLOBAL_AuthorContact | m | ||||
| GLOBAL_License | No license provided, ask the author for permission | m | |||
| GLOBAL_Organization | m | ||||
| GLOBAL_DatabaseName | m | ||||
| GLOBAL_SubjectID | m | ||||
| GLOBAL_RoomType | free field | m | |||
| GLOBAL_DataType | FIR | rm | |||
| GLOBAL_History | |||||
| GLOBAL_Comment | |||||
| GLOBAL_DatabaseTimeCreated | m | will be updated when saving and not existing or empty | |||
| GLOBAL_DatabaseTimeModified | m | will be updated each time when saving | |||
| ListenerPosition | [1 0 0] | m | IC, MC | double | |
| ListenerPosition_Type | cartesian | m | |||
| ListenerPosition_Units | meter | m | |||
| ListenerUp | [1.2 0 1] | m | IC, MC | double | |
| ListenerUp_Type | cartesian | m | |||
| ListenerUp_Units | meter | m | |||
| ListenerView | [0 0 0] | m | IC, MC | double | |
| ListenerView_Type | cartesian | m | |||
| ListenerView_Units | meter | m | |||
| ListenerRotation | [0 0 0] | m | IC, MC | double | |
| ListenerRotation_Type | din9300 | m | |||
| ListenerRotation_Units | degrees | m | |||
| ReceiverPosition | [0 -0.09 0; 0 0.09 0] | m | rCI, rCM | double | |
| ReceiverPosition_Type | cartesian | m | |||
| ReceiverPosition_Units | meter | m | |||
| SourcePosition | [0 0 0] | m | IC, MC | double | |
| SourcePosition_Type | cartesian | m | |||
| SourcePosition_Units | meter | m | |||
| EmitterPosition | [0 0 0] | m | eCI, eCM | double | |
| EmitterPosition_Type | cartesian | m | |||
| EmitterPosition_Units | meter | m | |||
| Data.IR | [1 1] | m | mRn | double | |
| Data.SamplingRate | 48000 | m | I | double | |
| Data.SamplingRate_Units | hertz | m | |||
| Data.Delay | [0 0] | m | IR, MR | double |
Legend:
- Name: the name of the metadata
- An underscore (_): the metadata is an attribute
- GLOBAL_: the metadata is a global attribute
- X_Y: the metadata is an attribute Y of the variable X
- No underscore: the metadata is a variable
- Data.X: the metadata is structured within the data
- An underscore (_): the metadata is an attribute
- Default: default value for the metadata
- An asterisk (*): special handling required, mentioned in the column Comment
- Flags:
- r: read-only, must be the default value
- m: mandatory, must be saved in the file
- Dimensions: dimensions of the metadata (see SOFA specifications for more explanations)
- lower case: the variable size in that dimension determines the dimension size in the file
- upper case: variable must be of that dimension (or one of these dimensions)
Stable (used in SOFA 0.3)
| Name | Default | Flags | Dimensions | Comment |
|---|---|---|---|---|
| GLOBAL_Conventions | SOFA | rm | ||
| GLOBAL_Version | 0.3 | rm | ||
| GLOBAL_SOFAConventions | SimpleFreeFieldHRIR | rm | ||
| GLOBAL_SOFAConventionsVersion | 0.1 | m | ||
| GLOBAL_APIName | * | rm | Insert the API Name here | |
| GLOBAL_APIVersion | * | rm | Insert the API Version here | |
| GLOBAL_ApplicationName | m | |||
| GLOBAL_ApplicationVersion | m | |||
| GLOBAL_AuthorContact | m | |||
| GLOBAL_License | No license provided, ask the author for permission | m | ||
| GLOBAL_Organization | m | |||
| GLOBAL_DatabaseName | m | |||
| GLOBAL_SubjectID | m | |||
| GLOBAL_RoomType | free field | m | ||
| GLOBAL_DataType | FIR | m | ||
| GLOBAL_History | ||||
| GLOBAL_Comment | ||||
| GLOBAL_DatabaseTimeCreated | * | m | will be updated when saving and not existing or empty | |
| GLOBAL_DatabaseTimeModified | * | m | will be updated each time when saving | |
| I | 1 | rm | I | |
| I_LongName | singleton dimension | rm | ||
| R | 2 | rm | R | |
| R_LongName | number of receivers | rm | ||
| E | 1 | rm | E | |
| E_LongName | number of emitters | rm | ||
| N | - | m | N | |
| N_LongName | time | m | ||
| N_Units | samples | m | ||
| M | - | m | M | |
| M_LongName | number of measurements | rm | ||
| C | 3 | rm | C | |
| C_LongName | coordinate triplet | rm | ||
| ListenerPosition | [1 0 0] | m | IC, MC | |
| ListenerPosition_Type | cartesian | m | ||
| ListenerPosition_Unitsmeter | m | |||
| ListenerUp | [1.2 0 1] | m | IC, MC | |
| ListenerUp_Type | cartesian | m | ||
| ListenerUp_Units | meter | m | ||
| ListenerView | [0 0 0] | m | IC, MC | |
| ListenerView_Type | cartesian | m | ||
| ListenerView_Units | meter | m | ||
| ListenerRotation | [0 0 0] | m | IC, MC | |
| ListenerRotation_Type | din9300 | m | ||
| ListenerRotation_Units | degrees | m | ||
| ReceiverPosition | [0 -0.09 0; 0 0.09 0] | m | rCI, rCM | |
| ReceiverPosition_Type | cartesian | m | ||
| ReceiverPosition_Units | meter | m | ||
| SourcePosition | [0 0 0] | m | IC, MC | |
| SourcePosition_Type | cartesian | m | ||
| SourcePosition_Units | meter | m | ||
| SourceUp | [0 0 1] | m | IC, MC | |
| SourceUp_Type | cartesian | m | ||
| SourceUp_Units | meter | m | ||
| SourceView | [1 0 0] | m | IC, MC | |
| SourceView_Type | cartesian | m | ||
| SourceView_Units | meter | m | ||
| EmitterPosition | [0 0 0] | m | eCI, eCM | |
| EmitterPosition_Type | cartesian | m | ||
| EmitterPosition_Units | meter | m | ||
| Data.IR | [1 1] | m | mRn | |
| Data.SamplingRate | 48000 | m | I | |
| Data.SamplingRate_Units | hertz | m |
Legend:
- Name: the name of the metadata
- An underscore (_): the metadata is an attribute
- GLOBAL_: the metadata is a global attribute
- X_Y: the metadata is an attribute Y of the variable X
- No underscore: the metadata is a variable
- Data.X: the metadata is structured within the data
- An underscore (_): the metadata is an attribute
- Default: default value for the metadata
- An asterisk (*): special handling required, mentioned in the column Comment
- Flags:
- r: read-only, must be the default value
- m: mandatory, must be saved in the file
- Dimensions: dimensions of the metadata (see SOFA specifications for more explanations)
- lower case: the variable size in that dimension determines the dimension size in the file
- upper case: variable must be of that dimension (or one of these dimensions)