Configs/.config/wireplumber/scripts/suspend-node.lua

-- WirePlumber
--
-- Copyright © 2021 Collabora Ltd.
--    @author George Kiagiadakis <george.kiagiadakis@collabora.com>
--
-- SPDX-License-Identifier: MIT

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

sources = {}

om:connect("object-added", function (om, node)
  node:connect("state-changed", function (node, old_state, cur_state)
    -- Always clear the current source if any
    local id = node["bound-id"]
    if sources[id] then
      sources[id]:destroy()
      sources[id] = nil
    end

    -- Add a timeout source if idle for at least 5 seconds
    if cur_state == "idle" or cur_state == "error" then
      -- honor "session.suspend-timeout-seconds" if specified
      local timeout =
          tonumber(node.properties["session.suspend-timeout-seconds"]) or 5

      if timeout == 0 then
        return
      end

      -- add idle timeout; multiply by 1000, timeout_add() expects ms
      sources[id] = Core.timeout_add(timeout * 1000, function()
        -- Suspend the node
        Log.info(node, "was idle for a while; suspending ...")
        node:send_command("Suspend")

        -- Unref the source
        sources[id] = nil

        -- false (== G_SOURCE_REMOVE) destroys the source so that this
        -- function does not get fired again after 5 seconds
        return false
      end)
    end

  end)
end)

om:activate()