Source Code for Module timeside.grapher.spectrogram_lin

 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  from timeside.grapher.spectrogram_log import SpectrogramLog 
26   
27   
28 -class SpectrogramLinear(SpectrogramLog): 
29      """ Builds a PIL image representing a spectrogram of the audio stream (level vs. frequency vs. time). 
30      Adds pixels iteratively thanks to the adapter providing fixed size frame buffers.""" 
31   
32      implements(IGrapher) 
33   
34      @interfacedoc 
35 -    def __init__(self, width=1024, height=256, bg_color=(0,0,0), color_scheme='default'): 
36          super(SpectrogramLinear, self).__init__(width, height, bg_color, color_scheme) 
37   
38      @staticmethod 
39      @interfacedoc 
40 -    def id(): 
41          return "spectrogram_lin" 
42   
43      @staticmethod 
44      @interfacedoc 
45 -    def name(): 
46          return "Spectrogram linear" 
47   
48      @interfacedoc 
49 -    def setup(self, channels=None, samplerate=None, blocksize=None, totalframes=None): 
50          super(SpectrogramLinear, self).setup(channels, samplerate, blocksize, totalframes) 
51   
52 -    def set_scale(self): 
53          """generate the lookup which translates y-coordinate to fft-bin""" 
54   
55          f_min = float(self.lower_freq) 
56          f_max = float(self.higher_freq) 
57          y_min = f_min 
58          y_max = f_max 
59          for y in range(self.image_height): 
60              freq = y_min + y / (self.image_height - 1.0) *(y_max - y_min) 
61              fft_bin = freq / f_max * (self.fft_size/2 + 1) 
62              if fft_bin < self.fft_size/2: 
63                  alpha = fft_bin - int(fft_bin) 
64                  self.y_to_bin.append((int(fft_bin), alpha * 255)) 
65