A Home Assistant blueprint for emulating the Nest Hub doorbell notification with any sound and feed, uses WebRTC and DashCast custom components

doorbell-cast-blueprint.yaml

blueprint:
  name: Doorbell cast notification
  description: A script that emulates the Nest Hub doorbell notification with any sound and feed
  domain: script
  source_url: https://gist.github.com/MattJeanes/0bb4cb11f20b327809b7e7f1d45921be
  author: MattJeanes
  input:
    notify_device:
      name: Device to notify
      description: Device to cast the sound and doorbell camera to
      selector:
        entity:
          filter:
            domain: media_player
    camera:
      name: Camera feed
      description: Camera feed to cast
      selector:
        entity:
          filter:
            domain: camera
    sound:
      name: "Sound"
      description: "The sound to play before casting the camera, e.g. doorbell ringing / spoken message"
      selector:
        media:
    ha_url:
      name: "Home Assistant URL"
      description: "URL to Home Assistant instance, must include protocol e.g. http/https and port if appropriate"
      selector:
        text:
    duration:
      name: "Duration"
      description: "How long the camera feed should cast for before dismissing automatically"
      selector:
        duration:
      default:
        hours: 0
        minutes: 0
        seconds: 30
mode: single
sequence:
  - variables:
      link_id: "{% for _ in range(40) %}{{ range(10)|random }}{% endfor %}"
      ha_url: !input ha_url
      sound: !input sound
  - service: webrtc.create_link
    data:
      entity: !input camera
      link_id: "{{ link_id }}"
      time_to_live: 60
      open_limit: 1
    enabled: true
  - if:
      - condition: not
        conditions:
          - condition: state
            entity_id: !input notify_device
            state: "off"
    then:
      - service: media_player.turn_off
        data: {}
        target:
          entity_id: !input notify_device
      - wait_for_trigger:
          - platform: state
            entity_id:
              - !input notify_device
            to: "off"
        timeout:
          hours: 0
          minutes: 0
          seconds: 2
          milliseconds: 0
      - delay:
          hours: 0
          minutes: 0
          seconds: 1
          milliseconds: 0
  - service: media_player.play_media
    target:
      entity_id: !input notify_device
    data:
      media_content_id:  "{{ sound.media_content_id }}"
      media_content_type:  "{{ sound.media_content_type }}'"
      extra:
        thumb: "https://brands.home-assistant.io/_/homeassistant/logo.png"
        title: Doorbell
  - wait_for_trigger:
      - platform: state
        entity_id:
          - !input notify_device
        from: playing
        to: idle
    timeout:
      hours: 0
      minutes: 0
      seconds: 10
      milliseconds: 0
  - service: dash_cast.load_url
    data:
      entity_id: !input notify_device
      url: "{{ ha_url }}/webrtc/embed?url={{ link_id }}&mode=mse"
      force: true
    enabled: true
  - delay: !input duration
  - if:
      - condition: state
        entity_id: !input notify_device
        attribute: app_name
        state: DashCast
        for:
          hours: 0
          minutes: 0
          seconds: 0
    then:
      - service: media_player.turn_off
        data: {}
        target:
          entity_id: !input notify_device