Lua script for OBS to display current time and a frame counter in a text source

obs-time-frame.lua

script_ver    = 2.5
obs           = obslua
source_name   = ""

last_text     = ""
current_frame = 0

time_format_string   = ""
output_format_string = ""

output_fomart_string_vars = {
	time = {
		desc = "Output from the <strong>Time Format String</strong>",
		func = function() return os.date(time_format_string) end
	},
	cfn = {
		desc = "Current frame number",
		func = function() return string.format("%02d", current_frame) end
	}
}

ffi = require("ffi")

ffi.cdef[[
struct video_output;
typedef struct video_output video_t;

double video_output_get_frame_rate(const video_t *video);

video_t *obs_get_video(void);
]]

local obsffi
if ffi.os == "OSX" then
    obsffi = ffi.load("obs.0.dylib")
else
    obsffi = ffi.load("obs")
end

-- Function to set the time text
function set_text()
	local text = string.gsub(output_format_string, "%%(%w+)", function(var)
		if (output_fomart_string_vars[var]) then
			return output_fomart_string_vars[var].func()
		else
			return "%"..var
		end
	end)

	if text ~= last_text then
		local source = obs.obs_get_source_by_name(source_name)
		if source ~= nil then
			local settings = obs.obs_data_create()
			obs.obs_data_set_string(settings, "text", text)
			obs.obs_source_update(source, settings)
			obs.obs_data_release(settings)
			obs.obs_source_release(source)
		end
	end

	last_text = text
end

-- Function to set the frame number
function set_frame()
	current_frame = current_frame + 1
	if current_frame > video_output_get_frame_rate() then
		current_frame = 1
	end
end

function obs_get_video()
	return obsffi.obs_get_video()
end

function video_output_get_frame_rate()
	return obsffi.video_output_get_frame_rate(obs_get_video());
end

function reset(pressed)
	if not pressed then
		return
	end

	local source = obs.obs_get_source_by_name(source_name)
	if source ~= nil then
		local active = obs.obs_source_active(source)
		obs.obs_source_release(source)
	end
end

----------------------------------------------------------

-- Called every frame (by OBS)
function script_tick(sec)
	set_frame()
	set_text()
end

-- A function named script_properties defines the properties that the user
-- can change for the entire script module itself
function script_properties()
	local props = obs.obs_properties_create()

	local p = obs.obs_properties_add_list(props, "source", "Text Source", obs.OBS_COMBO_TYPE_EDITABLE, obs.OBS_COMBO_FORMAT_STRING)
	local sources = obs.obs_enum_sources()
	if sources ~= nil then
		for _, source in ipairs(sources) do
			source_id = obs.obs_source_get_id(source)
			if source_id == "text_gdiplus" or source_id == "text_ft2_source" or source_id == "text_ft2_source_v2" then
				local name = obs.obs_source_get_name(source)
				obs.obs_property_list_add_string(p, name, name)
			end
		end
	end
	obs.source_list_release(sources)

	obs.obs_properties_add_text(props, "time_format_string", "Time Format String", obs.OBS_TEXT_DEFAULT)
	obs.obs_properties_add_text(props, "output_format_string", "Output Format String", obs.OBS_TEXT_DEFAULT)

	return props
end

function script_description()
	local desc = [[
<style>
#output_vars {
	margin: 10px 0 10px 10px;
}
#output_vars td {
	padding: 5px;
	border: 1px solid #888;
}
#author, #script_var {
	margin-top: 5px;
}
</style>

<h3>Sets a text source to act as a date/time and frame count.</h3>

Available <strong>Output Format String</strong> Variables
<table id="output_vars">
	<tbody>
]]

	for name,value in pairs(output_fomart_string_vars) do
		desc = desc .. [[
		<tr>
			<td width="55"><code>%]] .. name .. [[</code></td>
			<td>]] .. value.desc .. [[</td>
		</tr>
]]
	end

	desc = desc .. [[
	</tbody>
</table>

<div id="author">Made by Ragowit and modified by us -- Use at your own risk!</div>

<div id="script_var"><small>Version: ]] .. script_ver .. [[</small></div>]]

	return desc
end

-- A function named script_update will be called when settings are changed
function script_update(settings)
	source_name = obs.obs_data_get_string(settings, "source")
	time_format_string = obs.obs_data_get_string(settings, "time_format_string")
	output_format_string = obs.obs_data_get_string(settings, "output_format_string")
	reset(true)
end

-- A function named script_defaults will be called to set the default settings
function script_defaults(settings)
	obs.obs_data_set_default_string(settings, "time_format_string", "%H:%M:%S")
	obs.obs_data_set_default_string(settings, "output_format_string", "%time [%cfn]")
end