Definition

Microphone Array Geometry is a Data Type representing the position of each microphone comprising a Microphone Array and specific characteristics such as microphone type, look directions, and the array type.

Syntax

https://schemas.mpai.community/CAE/V2.1/data/MicrophoneArrayGeometry.json

Semantics

Table 1 gives the Semantics of Microphone Array Geometry.

Table 1 – Semantics of Microphone Array Geometry

Label Size Description
HEADER 9 Bytes
·       Standard 7 Bytes The CAE-MAG string
·       Version 1 Byte Major version
·       Subversion 1 Byte Minor version
MAGID 16 Bytes UUID Identifier of the Microphone Array Geometry.
Microphone features
·       ArrayType bit 0-1 Indicates the type of microphone array positioning such as 00:Spherical, 01:Circular, 10:Planar, 11:Linear. (uint8)
·       ArrayScat bit 2 Indicates the type of the microphone array (0:Rigid, 1:Open). (uint8)
·       Reserved bit 2-7
·       ArrayFilterURI N Bytes A uniform resource identifier (URI) string identifying the path to a local or remote file containing specific filter coefficients of the microphone array to be used for equalisation. (string)
Sampling features
·       SamplingRate 0-3 bits 0:8, 1:16, 2:24, 3:32, 4:44.1, 5:48, 6: 64, 7: 96, 8: 192 (all kHz)
·       SampleType 4-5 bits 0:16, 1:24, 2:32, 3:64 (all bits/sample)
·       Reserved bit 6-7
NumberOfMicrophones
MicrophoneAttributes A list containing Microphone attributes.
·       MicrophoneID 1 Byte
·       xCoord 4 Bytes x position of the microphone in m. (number)
·       yCoord 4 Bytes y position of the microphone in m.(number)
·       zCoord 4 Bytes z position of the microphone in m.  (number)
·       directivity bit 0-2 The directivity pattern of the specific microphone, 000: omnidirectional, 001: figure of eight, 010: cardioid, 011: supercardioid, 100: hypercardioid (uint8)
·       Reserved Bit 3-7
·       micxLookCoord 4 Bytes x component of the vector representing the look direction of the microphone in m.  (number)
·       micyLookCoord 4 Bytes y component of the vector representing the look direction of the microphone in m.  (number)
·       miczLookCoord 4 Bytes z component of the vector representing the look direction of the microphone. (number)
MicrophoneArrayLookCoord
xLookCoord 4 Bytes x component of the vector representing the look direction of the microphone array. (number)
yLookCoord 4 Bytes y component of the vector representing the look direction of the microphone array. (number)
zLookCoord 4 Bytes z component of the vector representing the look direction of the microphone array. (number)