Simple Lua script for switching scene automatically in OBS

automagic-scene-switcher.lua

local settings = {
  active = false,
  main_scene_index = 1,
  main_scene_probability = 0.75,
  main_scene_min_duration_ms = 3000,
  main_scene_max_duration_ms = 5000,
  secondary_scene_min_duration_ms = 2000,
  secondary_scene_max_duration_ms = 3000,
}

local scenes = nil
local current_scene_index = settings.main_scene_index
local previous_scene_index = nil

local function pick_next_scene_index()
  local next_scene_index = nil
  repeat
    if math.random() < settings.main_scene_probability then
      next_scene_index = settings.main_scene_index
    else
      next_scene_index = math.random(settings.main_scene_index + 1, #scenes)
    end
  until next_scene_index ~= current_scene_index
    and (next_scene_index ~= previous_scene_index or next_scene_index == settings.main_scene_index)
  return next_scene_index
end

local function get_scene_duration_ms(scene_index)
  if scene_index == settings.main_scene_index then
    return math.random(settings.main_scene_min_duration_ms, settings.main_scene_max_duration_ms)
  end
  return math.random(settings.secondary_scene_min_duration_ms, settings.secondary_scene_max_duration_ms)
end

local function schedule_next_switch()
  obslua.timer_remove(switch_scene)
  local next_switch_after_ms = get_scene_duration_ms(current_scene_index)
  obslua.timer_add(switch_scene, next_switch_after_ms)
end

local function activate(active)
  if settings.active == active then return end
  if not active then obslua.timer_remove(switch_scene) return end
  schedule_next_switch()
end

function switch_scene()
  local next_scene_index = pick_next_scene_index()
  previous_scene_index = current_scene_index
  current_scene_index = next_scene_index
  obslua.obs_frontend_set_current_scene(scenes[current_scene_index])

  schedule_next_switch()
end

function script_load()
  math.randomseed(os.time())
  scenes = obslua.obs_frontend_get_scenes()
end

function script_description()
  return "<center>✨🎬 <strong>Automagic Scene Switcher</strong> 🎬✨</center>"
end

function script_properties()
  local properties = obslua.obs_properties_create()
  obslua.obs_properties_add_bool(properties, "active", "Active")
  obslua.obs_properties_add_float_slider(properties, "main_scene_probability", "Main scene probability", 0, 0.95, 0.05)
  obslua.obs_properties_add_int_slider(properties, "main_scene_min_duration_ms", "Main scene min duration (ms)", 100, 20000, 100)
  obslua.obs_properties_add_int_slider(properties, "main_scene_max_duration_ms", "Main scene max duration (ms)", 100, 20000, 100)
  obslua.obs_properties_add_int_slider(properties, "secondary_scene_min_duration_ms", "Secondary scene min duration (ms)", 100, 20000, 100)
  obslua.obs_properties_add_int_slider(properties, "secondary_scene_max_duration_ms", "Secondary scene max duration (ms)", 100, 20000, 100)
  return properties
end

function script_defaults(s)
  obslua.obs_data_set_default_bool(s, "active", settings.active)
  obslua.obs_data_set_default_double(s, "main_scene_probability", settings.main_scene_probability)
  obslua.obs_data_set_default_int(s, "main_scene_min_duration_ms", settings.main_scene_min_duration_ms)
  obslua.obs_data_set_default_int(s, "main_scene_max_duration_ms", settings.main_scene_max_duration_ms)
  obslua.obs_data_set_default_int(s, "secondary_scene_min_duration_ms", settings.secondary_scene_min_duration_ms)
  obslua.obs_data_set_default_int(s, "secondary_scene_max_duration_ms", settings.secondary_scene_max_duration_ms)
end

function script_update(s)
  local active = obslua.obs_data_get_bool(s, "active")
  activate(active)

  settings.active = active
  settings.main_scene_probability = obslua.obs_data_get_double(s, "main_scene_probability")
  settings.main_scene_min_duration_ms = obslua.obs_data_get_int(s, "main_scene_min_duration_ms")
  settings.main_scene_max_duration_ms = obslua.obs_data_get_int(s, "main_scene_max_duration_ms")
  settings.secondary_scene_min_duration_ms = obslua.obs_data_get_int(s, "secondary_scene_min_duration_ms")
  settings.secondary_scene_max_duration_ms = obslua.obs_data_get_int(s, "secondary_scene_max_duration_ms")
end

function script_unload()
  obslua.source_list_release(scenes)
end