Recorder node

The Recorder (recorder) node publishes start_recording / stop_recording to a twin’s webrtc-command MQTT topic so the media service persists the already-running WebRTC stream to its configured bucket. The node never carries the media itself — the camera or microphone must already be streaming.

Palette category: Actuation. Edge-only. Toggles persistence on the media service; it does not create the stream.

The Recorder node, the audio widget’s REC button in the environment view, and the microphone driver’s fallback relay all publish the exact same payload on cyberwave/twin/{uuid}/webrtc-command. The three paths converge on the same media-service handler and the same webrtc-command/status ACK, so you can mix and match without changing the consumer.

Inputs

Field	Type	Required	Description
`twin_uuid`	string	Yes	Twin whose stream should be recorded. Defaults to the workflow’s bound twin.
`command`	string	Yes	`start_recording` or `stop_recording`. Wire from an upstream Conditional / Fuzzy Matcher to toggle dynamically, or pin a literal in the inspector.
`frontend_type`	string	Yes	`video` or `audio`. The media service treats this as `audio` when unset.
`sensor`	string	Yes	Sensor identifier (e.g. `camera`, `mic`). Required by the media-service `start_recording` handler — commands without it are refused.
`stream_source`	string	No	Optional producer hint (e.g. `camera`).
`stream_instance_id`	string	No	Optional disambiguator when a twin publishes multiple streams under the same sensor.

MQTT payload

Published to {prefix}cyberwave/twin/{twin_uuid}/webrtc-command with QoS 1:

{
  "command": "start_recording",
  "source_type": "edge",
  "sensor": "camera",
  "frontend_type": "video",
  "stream_source": "camera",
  "stream_instance_id": "primary"
}

To stop, send the same payload with "command": "stop_recording". Status is published back by the media service on {prefix}cyberwave/twin/{twin_uuid}/webrtc-command/status.

Outputs

Field	Type	Description
`command`	string	Recording command that was published.
`topic`	string	Full MQTT topic the command was published to.
`payload`	object	Payload sent to the media service.
`sent`	boolean	Whether the broker accepted the publish.

Execution targets

Target	Behavior
Edge	Emitter renders a `client.mqtt.publish` against the twin-scoped `webrtc-command` topic in the generated worker.
Cloud	Not supported — the node raises at compile time for cloud workflows.

Audio in workflows
Virtual Controller — generic controller actuation publisher
Send MQTT — generic edge-side MQTT publish

Concepts

Platform Features

Cyberwave Edge

Technical Reference

Use-Case Recipes

Inputs

MQTT payload

Outputs

Execution targets

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​Related

Inputs

MQTT payload

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Related