Source Code for Module jazzparser.harmonical.output

 1  """Audio output for the harmonical. 
 2   
 3  Routines for preparing and using audio output. These rely on PyGame,  
 4  which is an optional dependency. 
 5   
 6  """ 
 7  """ 
 8  ============================== License ======================================== 
 9   Copyright (C) 2008, 2010-12 University of Edinburgh, Mark Granroth-Wilding 
10    
11   This file is part of The Jazz Parser. 
12    
13   The Jazz Parser is free software: you can redistribute it and/or modify 
14   it under the terms of the GNU General Public License as published by 
15   the Free Software Foundation, either version 3 of the License, or 
16   (at your option) any later version. 
17    
18   The Jazz Parser is distributed in the hope that it will be useful, 
19   but WITHOUT ANY WARRANTY; without even the implied warranty of 
20   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the 
21   GNU General Public License for more details. 
22    
23   You should have received a copy of the GNU General Public License 
24   along with The Jazz Parser.  If not, see <http://www.gnu.org/licenses/>. 
25   
26  ============================ End license ====================================== 
27   
28  """ 
29  __author__ = "Mark Granroth-Wilding <mark.granroth-wilding@ed.ac.uk>" 
30   
31  from jazzparser.utils.base import load_from_optional_package, \ 
32              load_optional_package 
33  from jazzparser.harmonical.files import SoundFile 
34  from StringIO import StringIO 
35  import wave 
36   
37 -def check_pygame(): 
38      """ 
39      Checks that PyGame can be imported and outputs an error if not. 
40       
41      """ 
42      load_optional_package('pygame', 'PyGame', "outputing audio") 
43       
44 -def init_mixer(): 
45      """ 
46      Check that the mixer's initialized and initialize it if not. 
47       
48      """ 
49      # Check PyGame is available 
50      # This will raise an error if it's not 
51      check_pygame() 
52      from pygame import init, mixer 
53      # Set the mixer settings before initializing everything 
54      mixer.pre_init(frequency=44100) 
55      init() 
56       
57 -def play_audio(samples, wait_for_end=False): 
58      """ 
59      Uses PyGame to play the audio samples given as a list of samples. 
60       
61      """ 
62      init_mixer() 
63      from pygame.mixer import music 
64      from pygame.sndarray import make_sound 
65      from pygame import USEREVENT, event 
66      import numpy 
67       
68      # Prepare the wave data to play 
69      # Make it stereo and the right number format 
70      smp_array = numpy.array(zip(samples,samples)).astype(numpy.int16) 
71       
72      # Generate the sound object from the sample array 
73      snd = make_sound(smp_array) 
74      # Set it playing 
75      channel = snd.play() 
76      # Set an event to be triggered when the music ends, so we can  
77      #  wait for it if necessary 
78      channel.set_endevent(USEREVENT) 
79       
80      if wait_for_end: 
81          # Wait until the music finishes 
82          event.wait() 
83