Example Stereo to 2 x Mono track Lua script

scripts/_stereo_to_mono.lua

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+ardour { ["type"] = "EditorAction", name = "Stereo to Mono",
+	license     = "MIT",
+	author      = "Ardour Team",
+	description = [[Convert a Stereo Track into two Mono Tracks]]
+}
+
+
+function factory (params) return function ()
+	-- http://manual.ardour.org/lua-scripting/class_reference/#ArdourUI:Selection
+	-- the Ardour Selection can include multiple items
+	-- (regions, tracks, ranges, markers, automation, midi-notes etc)
+	local sel = Editor:get_selection ()
+
+	-- for each track..
+	for t in sel.tracks:routelist ():iter () do
+		local track = t:to_track ()
+		if track:isnil() then goto next end
+
+		-- only audio tracks
+		local playlist = track:playlist ()
+		if playlist:data_type ():to_string () ~= "audio" then goto next end
+
+		-- skip tracks without any regions
+		if playlist:region_list ():size() == 0 then goto next end
+
+		-- we can't access diskstream n_channels()
+		local channels = track:n_inputs(): n_audio()
+
+		-- stereo only
+		if channels ~= 2 then goto next end
+
+		-- create 2 new tracks (using the name of the original track)(
+		local newtracks = Session:new_audio_track (2, 2, nil, 2, t:name(),  ARDOUR.PresentationInfo.max_order, ARDOUR.TrackMode.Normal)
+		assert (newtracks:size() == 2)
+
+		for r in playlist:region_list ():iter () do
+			local region = r:to_audioregion ()
+			local rl = ARDOUR.RegionVector ()
+			local _, rv = region:separate_by_channel (rl)
+			assert (rv[1]:size () == 2)
+			-- 1:1 mapping of regions to new tacks
+			local plc = 1
+			for nr in rv[1]:iter () do
+				local pl = newtracks:table()[plc]:playlist()
+				pl:add_region (nr, r:position(), 1, false, 0, 0, false)
+				plc = plc + 1
+			end
+		end
+
+		-- TODO remove the old track
+
+		-- drop references for good.
+		collectgarbage ()
+		::next::
+	end
+
+end end