Beamformer Data Characteristic

Created on June 21, 2022

The Audio Beamformer Data characteristic is used to allow the RVS Server to provide information about beamformers used in the voice session. The Audio Beamformer Data characteristic is optional.

The characteristic UUID shall be set to: TBD

Beamformer Data Characteristic Value

The Beamformer Data Characteristic contains up to 4 fields describing beam data from a beamformer running on the RVS Client as described in below.


Field

Size

Description

Beam Data 1

5 Octets

Beam 1 data.

Beam Data 2

5 Octets

Beam 2 data.

Beam Data 3

5 Octets

Beam 3 data.

Beam Data 4

5 Octets

Beam 4 data.

Beam Data Field

The format used for each Beam Data field in the Beamformer Data Characteristic is describes in Table below.


Bits 8

16

16

Beam Description

Confidence

Signal Noise Ratio


The Beam Description byte uses the format described in Table below.


Bits 0-3

Bit 4

Bit 5

Bits 6-7

Reserved

Selected

Triggered

Angle (0, 90, 270, 360)


The Confidence value is float between 0-1 that has been converted to an unsigned 16-bit integer. This value represents the confidence level of the keyword detector.
The Signal Noise Ratio is a signed 16-bit integer where 1 unit is equal to .01 SNR.

Client Characteristic Configuration Descriptor

A Client Characteristic Configuration descriptor shall be included in the Beamformer Data characteristic.

Beamformer Data Characteristic Behaviour

If the RVS Server supports the Beamformer Data characteristic, the RVS Server MAY notify on the Beamformer Data Characteristic if the audio session was initiated by a keyword before the Data characteristic is notified on.

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