{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "$id": "https://jambonz.org/schema/verbs/dub",
  "minVersion": "0.9.6",
  "title": "Dub",
  "description": "Manages audio dubbing tracks on a call. Allows adding, removing, and controlling auxiliary audio tracks that are mixed into the call audio. Used for background music, coaching whispers, or injecting audio from external sources.\n\n**Track Routing:** Tracks are heard by the party on whose call leg they are created. A dub verb in the main verb stack (A-leg) creates tracks heard by the caller. A dub verb nested in the dial verb's `dub` array creates tracks heard by the callee. When using injectCommand to play/say on a track from a different call leg, pass the target call's `call_sid` as the third argument to `session.injectCommand()` to route the command to the correct leg.",
  "type": "object",
  "properties": {
    "verb": {
      "const": "dub"
    },
    "id": {
      "type": "string",
      "description": "An optional unique identifier for this verb instance."
    },
    "action": {
      "type": "string",
      "description": "The dubbing action to perform.",
      "enum": [
        "addTrack",
        "removeTrack",
        "silenceTrack",
        "playOnTrack",
        "sayOnTrack"
      ]
    },
    "track": {
      "type": "string",
      "description": "The name of the audio track. Used to reference the track in subsequent dub actions.",
      "examples": [
        "background-music",
        "coach-whisper"
      ]
    },
    "play": {
      "type": "string",
      "format": "uri",
      "description": "URL of an audio file to play on the track. Used with 'playOnTrack' action."
    },
    "say": {
      "oneOf": [
        {
          "type": "string"
        },
        {
          "type": "object",
          "additionalProperties": true
        }
      ],
      "description": "Text to synthesize and play on the track. Used with 'sayOnTrack' action. Can be a string or a say configuration object."
    },
    "loop": {
      "type": "boolean",
      "description": "If true, loop the audio on the track continuously."
    },
    "gain": {
      "oneOf": [
        {
          "type": "number"
        },
        {
          "type": "string"
        }
      ],
      "description": "Audio gain for the track in dB. Use negative values to reduce volume.",
      "examples": [
        -10,
        0,
        6
      ]
    }
  },
  "required": [
    "action",
    "track"
  ],
  "examples": [
    {
      "verb": "dub",
      "action": "addTrack",
      "track": "bgm"
    },
    {
      "verb": "dub",
      "action": "playOnTrack",
      "track": "bgm",
      "play": "https://example.com/music.mp3",
      "loop": true,
      "gain": -15
    },
    {
      "verb": "dub",
      "action": "sayOnTrack",
      "track": "coach",
      "say": "Ask about their budget"
    },
    {
      "verb": "dub",
      "action": "removeTrack",
      "track": "bgm"
    }
  ]
}