class_docstr: Test encoding features
class_docstr_tok: ["Test","encoding","features"]
code: def generate_source(self):
      self.expected_total_frames = np.ceil(
          self.source_duration * self.samplerate
      ).astype(np.int)
  
      f0 = 440.0
      f = f0 * np.logspace(
          0, 4 / 12 * (self.channels - 1), self.channels, base=2
      )
      omega = 2.0 * pi * f / self.samplerate
      samples = np.empty((self.expected_total_frames, self.channels))
      for n in range(self.channels):
          samples[:, n] = 0.75 * np.sin(
              omega[n] * np.arange(self.expected_total_frames)
          )
      return samples
  
imports: from __future__ import division
  from math import pi
  import numpy
  from unit_timeside import *
  from timeside.plugins.decoder.utils import get_uri, get_media_uri_info
  from timeside.plugins.decoder.array import ArrayDecoder
  import os
  from tools import tmp_file_sink
label_desc: Use image node_id 1 for calling the TestEncoding obj's underlying member method code with example usage: obj.generate_source() and returns: samples