Example Stereo to 2 x Mono track Lua script

diff --git a/scripts/_stereo_to_mono.lua b/scripts/_stereo_to_mono.lua
new file mode 100644 (file)
index 0000000..81fa031
--- /dev/null
+++ b/scripts/_stereo_to_mono.lua
@@ -0,0 +1,57 @@
+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