Keyword Detect Characteristic
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.