AlexaCaptions 1
The AlexaCaptions
interface exposes directives and events to enable the inter-process communication (IPC) client to control and display Alexa captions.
Header
{
"namespace": "AlexaCaptions",
"version": 1
}
Directives
Outbound messages from the Alexa client about the display of Alexa captions.
renderCaptions
Provides the IPC client with the payload required to render a text-to-speech synchronized presentation of Alexa captions.
Example message
{ "header": { "version": 1 "namespace": "AlexaCaptions", "name": "renderCaptions" }, "payload": { "duration": {{NUMBER}}, "delay": {{NUMBER}} "captionLines": [ { "text": "{{STRING}}", "styles": [ { "charIndex": "{{STRING}}", "activeStyle": { "bold": {{BOOLEAN}}, "italic": {{BOOLEAN}}, "underline": {{BOOLEAN}} } }, ... ] }, ... ] } }
Payload parameters
Parameter | Description | Type |
---|---|---|
duration |
Number in milliseconds to determine how long the caption should be displayed on the screen. | number |
delay |
The amount of time that should pass before this frame is shown on the screen. | number |
captionLines |
Array of captionLines objects that represent caption lines. |
array |
captionLines.text |
Caption line text content. | string |
captionLines.styles |
Array of captionLines styles objects. |
array |
captionLines.styles.charIndex |
Caption content index to apply activeStyle to. |
string |
captionLines.styles.activeStyle |
Caption styles to apply. | object |
captionLines.styles.activeStyle.bold |
Indicates whether to apply bold. | Boolean |
captionLines.styles.activeStyle.italic |
Indicates whether to apply italics. | Boolean |
captionLines.styles.activeStyle.underline |
Indicates whether to apply underline. | Boolean |
setCaptionsState
The Alexa client sends this directive in response to the captionsStateRequest
event to inform the IPC client of the current state of the captions setting in the Alexa client.
Example message
{ "header": { "version": 1 "namespace": "AlexaCaptions", "name": "setCaptionsState" }, "payload": { "enabled": {{BOOLEAN}} } }
Payload parameters
Parameter | Description | Type |
---|---|---|
enabled |
Indicates if captions are currently enabled in the Alexa client. | Boolean |
Events
Inbound messages from the IPC client about the display of Alexa captions.
captionsStateChanged
Send this event to instruct the Alexa client to change the AlexaCaptions
setting state.
Example message
{ "header": { "version": 1 "namespace": "AlexaCaptions", "name": "captionsStateChanged" }, "payload": { "enabled": {{BOOLEAN}} } }
Payload parameters
Parameter | Description | Type |
---|---|---|
enabled |
Indicates whether to enable captions in the Alexa client. When true , the Alexa client sends the renderCaptions directive for Alexa responses supported by AlexaCaptions . |
Boolean |
captionsStateRequest
Send this event to request the Alexa client to return the current state of the captions setting.
The Alexa client responds with a setCaptionsState
directive.
Example message
{
"header": {
"version": 1
"namespace": "AlexaCaptions",
"name": "captionsStateRequest"
},
"payload": {}
}
Payload parameters
The payload is an empty object.
Related topics
Last updated: Aug 24, 2022