Source Code for Module timeside.grapher.spectrogram_log

 1  # -*- coding: utf-8 -*- 
 2  # 
 3  # Copyright (c) 2007-2010 Guillaume Pellerin <yomguy@parisson.com> 
 4  # Copyright (c) 2010 Olivier Guilyardi <olivier@samalyse.com> 
 5   
 6  # This file is part of TimeSide. 
 7   
 8  # TimeSide is free software: you can redistribute it and/or modify 
 9  # it under the terms of the GNU General Public License as published by 
10  # the Free Software Foundation, either version 2 of the License, or 
11  # (at your option) any later version. 
12   
13  # TimeSide is distributed in the hope that it will be useful, 
14  # but WITHOUT ANY WARRANTY; without even the implied warranty of 
15  # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the 
16  # GNU General Public License for more details. 
17   
18  # You should have received a copy of the GNU General Public License 
19  # along with TimeSide.  If not, see <http://www.gnu.org/licenses/>. 
20   
21   
22  from timeside.core import implements, interfacedoc 
23  from timeside.api import IGrapher 
24  from timeside.grapher.core import * 
25   
26   
27 -class SpectrogramLog(Grapher): 
28      """ Builds a PIL image representing a spectrogram of the audio stream (level vs. frequency vs. time). 
29      Adds pixels iteratively thanks to the adapter providing fixed size frame buffers.""" 
30   
31      implements(IGrapher) 
32   
33      @interfacedoc 
34 -    def __init__(self, width=1024, height=256, bg_color=(0,0,0), color_scheme='default'): 
35          super(SpectrogramLog, self).__init__(width, height, bg_color, color_scheme) 
36          self.lower_freq = 100 
37          self.colors = default_color_schemes[color_scheme]['spectrogram'] 
38          self.pixels = [] 
39          self.y_to_bin = [] 
40   
41      @staticmethod 
42      @interfacedoc 
43 -    def id(): 
44          return "spectrogram_log" 
45   
46      @staticmethod 
47      @interfacedoc 
48 -    def name(): 
49          return "SpectrogramLog" 
50   
51      @interfacedoc 
52 -    def setup(self, channels=None, samplerate=None, blocksize=None, totalframes=None): 
53          super(SpectrogramLog, self).setup(channels, samplerate, blocksize, totalframes) 
54          self.image = self.image.convert("P") 
55          self.image = self.image.transpose(Image.ROTATE_90) 
56          self.image.putpalette(interpolate_colors(self.colors, True)) 
57          self.set_scale() 
58   
59 -    def set_scale(self): 
60          """generate the lookup which translates y-coordinate to fft-bin""" 
61   
62          f_min = float(self.lower_freq) 
63          f_max = float(self.higher_freq) 
64          y_min = math.log10(f_min) 
65          y_max = math.log10(f_max) 
66          for y in range(self.image_height): 
67              freq = math.pow(10.0, y_min + y / (self.image_height - 1.0) *(y_max - y_min)) 
68              fft_bin = freq / f_max * (self.fft_size/2 + 1) 
69              if fft_bin < self.fft_size/2: 
70                  alpha = fft_bin - int(fft_bin) 
71                  self.y_to_bin.append((int(fft_bin), alpha * 255)) 
72   
73 -    def draw_spectrum(self, x, spectrum): 
74          for (index, alpha) in self.y_to_bin: 
75              self.pixels.append( int( ((255.0-alpha) * spectrum[index] + alpha * spectrum[index + 1] )) ) 
76          for y in range(len(self.y_to_bin), self.image_height): 
77              self.pixels.append(0) 
78   
79      @interfacedoc 
80 -    def process(self, frames, eod=False): 
81          if len(frames) != 1: 
82              chunk = frames[:,0].copy() 
83              chunk.shape = (len(chunk),1) 
84              for samples, end in self.pixels_adapter.process(chunk, eod): 
85                  if self.pixel_cursor < self.image_width: 
86                      (spectral_centroid, db_spectrum) = self.spectrum.process(samples, True) 
87                      self.draw_spectrum(self.pixel_cursor, db_spectrum) 
88                      self.pixel_cursor += 1 
89          return frames, eod 
90   
91      @interfacedoc 
92 -    def post_process(self): 
93          """ Apply last 2D transforms""" 
94          self.image.putdata(self.pixels) 
95          self.image = self.image.transpose(Image.ROTATE_90) 
96