vidi/Sampler.py

   1 #!/usr/bin/env python3
   2 #
   3 # Sampler - play video samples interactively according to midi messages
   4 #
   5 # Copyright (C) 2016  Antonio Ospite <ao2@ao2.it>
   6 #
   7 # This program is free software: you can redistribute it and/or modify
   8 # it under the terms of the GNU General Public License as published by
   9 # the Free Software Foundation, either version 3 of the License, or
  10 # (at your option) any later version.
  11 #
  12 # This program is distributed in the hope that it will be useful,
  13 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 # GNU General Public License for more details.
  16 #
  17 # You should have received a copy of the GNU General Public License
  18 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
  19
  20 import os
  21 import mido
  22
  23 import gi
  24 gi.require_version('Gst', '1.0')
  25 from gi.repository import Gst
  26 Gst.init(None)
  27
  28 from gi.repository import GObject
  29 GObject.threads_init()
  30
  31 import vidi
  32
  33 class Sampler(vidi.Player):
  34     def __init__(self, videofont_path):
  35         playbin = Gst.ElementFactory.make("playbin", "player")
  36         vidi.Player.__init__(self, playbin)
  37
  38         self.videofont_path = videofont_path
  39         self.last_note = None
  40
  41         self.uri = Gst.filename_to_uri(self.get_sample_path(self.last_note))
  42         self.pipeline.set_property("uri", self.uri)
  43         self.pipeline.connect("about-to-finish", self.on_about_to_finish)
  44
  45     def on_about_to_finish(self, element):
  46         element.set_property("uri", self.uri)
  47
  48     def get_sample_path(self, note):
  49         if note is None:
  50             sample_name = "rest"
  51         else:
  52             sample_name = vidi.MidiNote(note).name
  53
  54         return "%s/sample_%s.webm" % (self.videofont_path, sample_name)
  55
  56     def midi_message_cb(self, msg):
  57         if vidi.is_note(msg):
  58             new_note = msg.note
  59
  60             # The logic is as follows:
  61             #  - Always play a new note on;
  62             #  - only play silence if the note off is the same one that was
  63             #    played last;
  64             #  - otherwise do nothing.
  65             if vidi.is_note_on(msg):
  66                 note = new_note
  67             elif vidi.is_note_off(msg) \
  68                     and new_note == self.last_note:
  69                 note = None
  70             else:
  71                 note = self.last_note
  72
  73             if note != self.last_note:
  74                 self.last_note = note
  75                 sample_path = self.get_sample_path(note)
  76                 if os.path.exists(sample_path):
  77                     self.switch(sample_path)
  78                 else:
  79                     print("Warning: videofont is missing sample '%s'" % sample_path)
  80
  81     def switch(self, sample_path):
  82         print("Next: %s" % sample_path)
  83         self.uri = Gst.filename_to_uri(sample_path)
  84         seek_event = Gst.Event.new_seek(1.0,
  85                                         Gst.Format.TIME,
  86                                         Gst.SeekFlags.FLUSH,
  87                                         Gst.SeekType.END, -1,
  88                                         Gst.SeekType.NONE, 0)
  89         self.pipeline.send_event(seek_event)
  90
  91
  92 class DeviceSampler(Sampler):
  93     def __init__(self, videofont_path, midi_source_name):
  94         Sampler.__init__(self, videofont_path)
  95
  96         print(mido)
  97         midi_source = mido.open_input(midi_source_name)
  98         midi_source.callback = self.midi_message_cb
  99
 100
 101 class FileSampler(Sampler):
 102     def __init__(self, videofont_path, midi_file_name):
 103         Sampler.__init__(self, videofont_path)
 104
 105         self.midi_file = mido.MidiFile(midi_file_name)
 106         overlapping_notes = vidi.check_overlapping_notes(self.midi_file)
 107         if overlapping_notes:
 108             print("Sorry, supporting only midi file with no overlapping notes on channel 0")
 109             return None
 110
 111     def play(self):
 112         def next_midi_msg(midi_file_generator):
 113             try:
 114                 msg = midi_file_generator.__next__()
 115                 if vidi.is_note(msg) and msg.channel == 0:
 116                     self.midi_message_cb(msg)
 117                 return True
 118             except StopIteration:
 119                 self.stop()
 120                 return False
 121
 122
 123         GObject.timeout_add(1, next_midi_msg, self.midi_file.play())
 124         Sampler.play(self)