scripts/_vamp_onset_example.lua

   1 ardour { ["type"] = "Snippet", name = "Vamp Onset Detection Example" }
   2
   3 function factory () return function ()
   4
   5         -- get Editor selection
   6         -- http://manual.ardour.org/lua-scripting/class_reference/#ArdourUI:Editor
   7         -- http://manual.ardour.org/lua-scripting/class_reference/#ArdourUI:Selection
   8         local sel = Editor:get_selection ()
   9
  10         -- Instantiate a Vamp Plugin
  11         -- see http://manual.ardour.org/lua-scripting/class_reference/#ARDOUR:LuaAPI:Vamp
  12         --
  13         -- here: the "Queen Mary Note Onset Detector" Vamp plugin (which comes with Ardour)
  14         -- http://vamp-plugins.org/plugin-doc/qm-vamp-plugins.html#qm-onsetdetector
  15         local vamp = ARDOUR.LuaAPI.Vamp("libardourvampplugins:qm-onsetdetector", Session:nominal_sample_rate())
  16
  17         -- prepare table to hold results
  18         local onsets = {}
  19
  20         -- for each selected region
  21         -- http://manual.ardour.org/lua-scripting/class_reference/#ArdourUI:RegionSelection
  22         for r in sel.regions:regionlist ():iter () do
  23                 -- "r" is-a http://manual.ardour.org/lua-scripting/class_reference/#ARDOUR:Region
  24
  25                 -- prepare lua table to hold results for the given region (by name)
  26                 onsets[r:name ()] = {}
  27
  28                 -- callback to handle Vamp-Plugin analysis results
  29                 function callback (feats)
  30                         -- "feats" is-a http://manual.ardour.org/lua-scripting/class_reference/#Vamp:Plugin:FeatureSet
  31                         -- get the first output. here: Detected note onset times
  32                         local fl = feats:table()[0]
  33                         -- "fl" is-a http://manual.ardour.org/lua-scripting/class_reference/#Vamp:Plugin:FeatureList
  34                         -- which may be empty or not nil
  35                         if fl then
  36                                 -- iterate over returned features
  37                                 for f in fl:iter () do
  38                                         -- "f" is-a  http://manual.ardour.org/lua-scripting/class_reference/#Vamp:Plugin:Feature
  39                                         if f.hasTimestamp then
  40                                                 local fn = Vamp.RealTime.realTime2Frame (f.timestamp, 48000)
  41                                                 --print ("-", f.timestamp:toString(), fn)
  42                                                 table.insert (onsets[r:name ()],  fn)
  43                                         end
  44                                 end
  45                         end
  46                         return false -- continue, !cancel
  47                 end
  48
  49                 -- Configure Vamp plugin
  50                 --
  51                 -- One could query the Parameter and Program List:
  52                 --   http://manual.ardour.org/lua-scripting/class_reference/#Vamp:Plugin
  53                 -- but since the Plugin is known, we can directly refer to the plugin doc:
  54                 -- http://vamp-plugins.org/plugin-doc/qm-vamp-plugins.html#qm-onsetdetector
  55                 vamp:plugin ():setParameter ("dftype", 3);
  56                 vamp:plugin ():setParameter ("sensitivity", 50);
  57                 vamp:plugin ():setParameter ("whiten", 0);
  58                 -- in this case the above (3, 50, 0) is equivalent to
  59                 --vamp:plugin ():selectProgram ("General purpose");
  60
  61                 -- run the plugin, analyze the first channel of the audio-region
  62                 --
  63                 -- This uses a "high-level" convenience wrapper provided by Ardour
  64                 -- which reads raw audio-data from the region and and calls
  65                 --     f = vamp:plugin ():process (); callback (f)
  66                 vamp:analyze (r:to_readable (), 0, callback)
  67
  68                 -- get remaining features (end of analyis)
  69                 callback (vamp:plugin ():getRemainingFeatures ())
  70
  71                 -- reset the plugin (prepare for next iteration)
  72                 vamp:reset ()
  73         end
  74
  75         -- print results
  76         for n,o in pairs(onsets) do
  77                 print ("Onset analysis for region:", n)
  78                 for _,t in ipairs(o) do
  79                         print ("-", t)
  80                 end
  81         end
  82
  83 end end