Lua Script Example for Audio to Midi Transcription (work in progress)

scripts/_vamp_note_example.lua

@@ -0,0 +1,57 @@
+ardour { ["type"] = "Snippet", name = "Vamp Audio Transcription Example" }
+
+function factory () return function ()
+
+	-- simple progress information print()ing
+	--[[
+	local progress_total;
+	local progress_last;
+	function cb (_f, pos)
+		local progress = 100 * pos / progress_total;
+		if progress - progress_last > 5 then
+			progress_last = progress;
+			print ("Progress: ", progress)
+		end
+	end
+	--]]
+
+	-- get Editor selection
+	-- http://manual.ardour.org/lua-scripting/class_reference/#ArdourUI:Editor
+	-- http://manual.ardour.org/lua-scripting/class_reference/#ArdourUI:Selection
+	local sel = Editor:get_selection ()
+	local sr = Session:nominal_frame_rate ()
+
+	-- Instantiate a Vamp Plugin
+	-- see http://manual.ardour.org/lua-scripting/class_reference/#ARDOUR:LuaAPI:Vamp
+	local vamp = ARDOUR.LuaAPI.Vamp ("libardourvampplugins:qm-transcription", sr)
+
+	-- for each selected region
+	-- http://manual.ardour.org/lua-scripting/class_reference/#ArdourUI:RegionSelection
+	for r in sel.regions:regionlist ():iter () do
+		-- "r" is-a http://manual.ardour.org/lua-scripting/class_reference/#ARDOUR:Region
+
+		--[[
+		progress_total = r:to_readable ():readable_length ()
+		progress_last = 0
+		--]]
+		vamp:analyze (r:to_readable (), 0, nil --[[cb--]])
+		print ("-- Post Processing: ", r:name ())
+
+		-- post-processing takes longer than actually parsing the data :(
+		local f = vamp:plugin ():getRemainingFeatures ()
+
+		local fl = f:table ()[0]
+		print (" Time (sample) |  Len  | Midi-Note");
+		if fl then for f in fl:iter () do
+			assert (f.hasTimestamp and f.hasDuration);
+			local ft = Vamp.RealTime.realTime2Frame (f.timestamp, sr)
+			local fd = Vamp.RealTime.realTime2Frame (f.duration, sr)
+			local fn = f.values:at (0) -- midi note number
+			print (string.format (" %14d %7d %d", ft, fd, fn))
+		end end
+
+		-- reset the plugin (prepare for next iteration)
+		vamp:reset ()
+	end
+
+end end