Source Code for Module jazzparser.misc.chordlabel.midi

 1  from __future__ import absolute_import 
 2  """Midi processing for midi chord labeler. 
 3   
 4  """ 
 5  """ 
 6  ============================== License ======================================== 
 7   Copyright (C) 2008, 2010-12 University of Edinburgh, Mark Granroth-Wilding 
 8    
 9   This file is part of The Jazz Parser. 
10    
11   The Jazz Parser is free software: you can redistribute it and/or modify 
12   it under the terms of the GNU General Public License as published by 
13   the Free Software Foundation, either version 3 of the License, or 
14   (at your option) any later version. 
15    
16   The Jazz Parser is distributed in the hope that it will be useful, 
17   but WITHOUT ANY WARRANTY; without even the implied warranty of 
18   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the 
19   GNU General Public License for more details. 
20    
21   You should have received a copy of the GNU General Public License 
22   along with The Jazz Parser.  If not, see <http://www.gnu.org/licenses/>. 
23   
24  ============================ End license ====================================== 
25   
26  """ 
27  __author__ = "Mark Granroth-Wilding <mark.granroth-wilding@ed.ac.uk>"  
28   
29  from midi import NoteOnEvent 
30    
31 -def midi_to_emission_stream(segmidi, remove_empty=True, unique_notes=False): 
32      """ 
33      Get a list of emissions from the midi stream's note on events. 
34       
35      Returns a 2-tuple of the list of emissions and their  
36      corresponding start times in midi ticks. 
37       
38      @type segmidi: L{jazzparser.data.input.SegmentedMidiInput} 
39      @param segmidi: midi input 
40      @type remove_empty: bool 
41      @param remove_empty: remove any chunks that have no observations in them  
42          (default True) 
43       
44      """ 
45      chunks = [] 
46      start_times = [] 
47      tick_unit = segmidi.tick_unit 
48       
49      for segment in segmidi: 
50          segment_start = segment.segment_start 
51          start_times.append(segment_start) 
52          note_ons = [ev for ev in segment.trackpool if isinstance(ev, NoteOnEvent)] 
53           
54          # Produce an observation for every event 
55          chunk = [] 
56          for ev in note_ons: 
57              pc = ev.pitch % 12 
58              chunk.append(pc) 
59          chunks.append(chunk) 
60           
61      # Get rid of duplicate values in the chunks (octaves) 
62      if unique_notes: 
63          chunks = [list(set(c)) for c in chunks] 
64      if remove_empty: 
65          # Remove chunks that have no observations in them 
66          chunks = [ems for ems in chunks if len(ems) > 0] 
67      chunks_times = zip(chunks, start_times) 
68       
69      # Return a tuple of the chunks and the start times 
70      return zip(*chunks_times) 
71