Lua DSP LTC decoder plugin

diff --git a/scripts/ltc_reader.lua b/scripts/ltc_reader.lua
new file mode 100644 (file)
index 0000000..be1490c
--- /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
+