Lua DSP LTC decoder plugin

1 files changed, 82 insertions, 0 deletions

diff --git a/scripts/ltc_reader.lua b/scripts/ltc_reader.lua
new file mode 100644
index 0000000000..be1490ca09
--- /dev/null
+++ b/scripts/ltc_reader.lua
@@ -0,0 +1,82 @@
+ardour {
+	["type"]    = "dsp",
+	name        = "LTC Reader",
+	category    = "Utility",
+	author      = "Ardour team",
+	license     = "MIT",
+	description = [[Linear Timecode Decoder with mixer strip inline display]]
+}
+
+function dsp_ioconfig ()
+	return { { audio_in = 1, audio_out = 1}, }
+end
+
+function dsp_init (rate)
+	timeout = rate
+	samplerate = rate
+	ltc_reader = ARDOUR.DSP.LTCReader (rate / 25, ARDOUR.DSP.LTC_TV_STANDARD.LTC_TV_FILM_24)
+	self:shmem():allocate(5)
+end
+
+function dsp_run (ins, outs, n_samples)
+	if ins[1] ~= outs[1] then
+		ARDOUR.DSP.copy_vector (outs[1]:offset (0), ins[1]:offset (0), n_samples)
+	end
+	ltc_reader:write (ins[1]:offset (0), n_samples, -1)
+	timeout = timeout + n_samples
+	local to_ui = self:shmem():to_int(0):array()
+	local rv
+	repeat
+		local tc
+		rv, tc =  ltc_reader:read (0, 0, 0, 0)
+		if rv then
+			timeout = 0
+			self:shmem():atomic_set_int (0, 1)
+			self:shmem():atomic_set_int (1, tc[1])
+			self:shmem():atomic_set_int (2, tc[2])
+			self:shmem():atomic_set_int (3, tc[3])
+			self:shmem():atomic_set_int (4, tc[4])
+			self:queue_draw ()
+		end
+	until not rv
+	if timeout > samplerate then
+		if 0 ~= self:shmem():atomic_get_int (0) then
+			self:shmem():atomic_set_int (0, 0)
+			self:queue_draw ()
+		end
+	end
+end
+
+-------------------------------------------------------------------------------
+-- inline UI
+--
+local txt = nil -- a pango context
+local vpadding = 2
+
+function render_inline (ctx, displaywidth, max_h)
+	if not txt then
+		txt = Cairo.PangoLayout (ctx, "Mono 10px")
+	end
+
+	local d = self:shmem():to_int(0):array()
+	if d[1] == 0 then
+		txt:set_text("--:--:--:--")
+	else
+		txt:set_text(string.format("%02d:%02d:%02d:%02d", d[2], d[3], d[4], d[5]))
+	end
+
+	-- compute the size of the display
+	local txtwidth, lineheight = txt:get_pixel_size()
+	local displayheight = math.min(vpadding + (lineheight + vpadding), max_h)
+
+	-- clear background
+	ctx:rectangle (0, 0, displaywidth, displayheight)
+	ctx:set_source_rgba (.2, .2, .2, 1.0)
+	ctx:fill ()
+	ctx:set_source_rgba (.8, .8, .8, 1.0)
+	ctx:move_to ((displaywidth - txtwidth) / 2, 1)
+	txt:show_in_cairo_context (ctx)
+
+	return {displaywidth, displayheight}
+end
+