Add script to normalize all tracks

diff --git a/scripts/normalize_all_tracks.lua b/scripts/normalize_all_tracks.lua
new file mode 100644 (file)
index 0000000..2886c9b
--- /dev/null
+++ b/scripts/normalize_all_tracks.lua
@@ -0,0 +1,58 @@
+ardour { ["type"] = "EditorAction",
+       name = "Normalize All Tracks",
+       license     = "MIT",
+       author      = "Ardour Team",
+       description = [[Normalize all regions using a common gain-factor per track.]]
+}
+
+function factory () return function ()
+       -- target values -- TODO: use a LuaDialog.Dialog and ask..
+       local target_peak = -1 --dBFS
+       local target_rms = -18 --dBFS/RMS
+
+       -- prepare undo operation
+       Session:begin_reversible_command ("Normalize Tracks")
+       local add_undo = false -- keep track if something has changed
+
+       -- loop over all tracks in the session
+       for track in Session:get_tracks():iter() do
+               local norm = 0 -- per track gain
+               -- loop over all regions on track
+               for r in track:to_track():playlist():region_list():iter() do
+                       -- test if it's an audio region
+                       local ar = r:to_audioregion ()
+                       if ar:isnil () then goto next end
+
+                       local peak = ar:maximum_amplitude (nil)
+                       local rms  = ar:rms (nil)
+                       -- check if region is silent
+                       if (peak > 0) then
+                               local f_rms = rms / 10 ^ (.05 * target_rms)
+                               local f_peak = peak / 10 ^ (.05 * target_peak)
+                               local tg = (f_peak > f_rms) and f_peak or f_rms  -- max (f_peak, f_rms)
+                               norm = (tg > norm) and tg or norm -- max (tg, norm)
+                       end
+                       ::next::
+               end
+
+               -- apply same gain to all regions on track
+               if norm > 0 then
+                       for r in track:to_track():playlist():region_list():iter() do
+                               local ar = r:to_audioregion ()
+                               if ar:isnil () then goto skip end
+                               ar:to_stateful ():clear_changes ()
+                               ar:set_scale_amplitude (1 / norm)
+                               add_undo = true
+                               ::skip::
+                       end
+               end
+       end
+
+       -- all done. now commit the combined undo operation
+       if add_undo then
+               -- the 'nil' command here means to use all collected diffs
+               Session:commit_reversible_command (nil)
+       else
+               Session:abort_reversible_command ()
+       end
+end end