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livetrax/scripts/_vamp_onset_example.lua

84 lines
3.1 KiB
Lua

ardour { ["type"] = "Snippet", name = "Vamp Onset Detection Example" }
function factory () return function ()
-- 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 ()
-- Instantiate a Vamp Plugin
-- see http://manual.ardour.org/lua-scripting/class_reference/#ARDOUR:LuaAPI:Vamp
--
-- here: the "Queen Mary Note Onset Detector" Vamp plugin (which comes with Ardour)
-- http://vamp-plugins.org/plugin-doc/qm-vamp-plugins.html#qm-onsetdetector
local vamp = ARDOUR.LuaAPI.Vamp("libardourvampplugins:qm-onsetdetector", Session:nominal_sample_rate())
-- prepare table to hold results
local onsets = {}
-- 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
-- prepare lua table to hold results for the given region (by name)
onsets[r:name ()] = {}
-- callback to handle Vamp-Plugin analysis results
function callback (feats)
-- "feats" is-a http://manual.ardour.org/lua-scripting/class_reference/#Vamp:Plugin:FeatureSet
-- get the first output. here: Detected note onset times
local fl = feats:table()[0]
-- "fl" is-a http://manual.ardour.org/lua-scripting/class_reference/#Vamp:Plugin:FeatureList
-- which may be empty or not nil
if fl then
-- iterate over returned features
for f in fl:iter () do
-- "f" is-a http://manual.ardour.org/lua-scripting/class_reference/#Vamp:Plugin:Feature
if f.hasTimestamp then
local fn = Vamp.RealTime.realTime2Frame (f.timestamp, 48000)
--print ("-", f.timestamp:toString(), fn)
table.insert (onsets[r:name ()], fn)
end
end
end
return false -- continue, !cancel
end
-- Configure Vamp plugin
--
-- One could query the Parameter and Program List:
-- http://manual.ardour.org/lua-scripting/class_reference/#Vamp:Plugin
-- but since the Plugin is known, we can directly refer to the plugin doc:
-- http://vamp-plugins.org/plugin-doc/qm-vamp-plugins.html#qm-onsetdetector
vamp:plugin ():setParameter ("dftype", 3);
vamp:plugin ():setParameter ("sensitivity", 50);
vamp:plugin ():setParameter ("whiten", 0);
-- in this case the above (3, 50, 0) is equivalent to
--vamp:plugin ():selectProgram ("General purpose");
-- run the plugin, analyze the first channel of the audio-region
--
-- This uses a "high-level" convenience wrapper provided by Ardour
-- which reads raw audio-data from the region and and calls
-- f = vamp:plugin ():process (); callback (f)
vamp:analyze (r:to_readable (), 0, callback)
-- get remaining features (end of analyis)
callback (vamp:plugin ():getRemainingFeatures ())
-- reset the plugin (prepare for next iteration)
vamp:reset ()
end
-- print results
for n,o in pairs(onsets) do
print ("Onset analysis for region:", n)
for _,t in ipairs(o) do
print ("-", t)
end
end
end end