rec.lua

#!/usr/bin/env wpexec

om = ObjectManager {
  Interest {
    type = "node",
    Constraint { "media.class", "=", "Video/Source" },
  },
  Interest {
    type = "node",
    Constraint { "media.class", "=", "Audio/Source" },
  },
}

running_sources = 0

function state_change(node, old_state, new_state)
  Log.debug("State changed: " .. node.properties["object.id"] .. ": " .. old_state .. " -> " .. new_state)
  
  if old_state == "running" then
    running_sources = running_sources - 1
    if running_sources == 0 then
      print()
    end
  elseif new_state == "running" then
    if running_sources == 0 then
      print("●")
    end
    running_sources = running_sources + 1
  end
end

om:connect("object-added", function(_, node)
  Log.debug("New source: " .. node.properties["object.id"] .. " " .. tostring(node.properties["node.name"]))
  Log.debug(node.properties["media.class"])
  
  node:connect("state-changed", state_change)
  state_change(node, "nonexistent", node.state)
end)

om:connect("object-removed", function(_, node)
  Log.debug("Source removed: " .. node.properties["object.id"] .. " " .. tostring(node.properties["node.name"]))
  state_change(node, node.state, "nonexistent")
end)

om:activate()