Keyword Detect Characteristic

Created on June 21, 2022

The Keyword Detect characteristic is used to allow the RVS Client to provide information to the RVS Server about a keyword detect that initiated the voice session. The Audio Keyword Detect characteristic is optional.

The characteristic UUID shall be set to:  TBD

Client Characteristic Configuration Descriptor

A Client Characteristic Configuration descriptor shall be included in the Keyword Detect characteristic.

Keyword Detect Characteristic Value

The Keyword Detect Characteristic contains 6 fields specifying information about a keyword detection that initiated the voice session as described in Table below.


Field

Size

Description

Pre-Keyword Sample Qty

4 Octets

The Pre-Keyword Sample Qty is a value that represents the number of samples available prior to the start of the keyword.

Keyword Sample Qty

4 Octets

The Keyword Sample Qty is a value that represents the number of samples contained in the keyword.

Estimated Direction of Arrival

2 Octets

The Estimated Direction of Arrival is a value that represents the angle at which the audio is being captured from (0-360 deg).

Standard Search Point

1 Octet

The Standard Search Point represents the sensitivity of the first level keyword detector.

High Search Point

1 Octet

The High Search Point represents the sensitivity of the second level keyword detector. This value can be set to 0xFF if the second level keyword detector does not exist or is disabled.

Dynamic Gain

1 Octet

The Dynamic Gain represents the amount of gain applied to the audio stream.

Keyword Detect Characteristic Behaviour

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

Go To Top