def test_frequency_impulse_response_gives_correct_size(
self, fft_size, window_size):
"""Tests generating impulse responses from a list of magnitudes.
The output size should be determined by the window size, or fft_size if
window size < 1.
Args:
fft_size: Size of the fft that generated the magnitudes.
window_size: Size of window to apply to inverse fft.
"""
# Create random signals to convolve.
n_frequencies = fft_size // 2 + 1
magnitudes = np.random.uniform(size=(1,
n_frequencies)).astype(np.float32)
impulse_response = core.frequency_impulse_response(
magnitudes, window_size)
target_size = fft_size
if target_size > window_size >= 1:
target_size = window_size
is_even = target_size % 2 == 0
target_size -= int(is_even)
impulse_response_size = int(impulse_response.shape[-1])
self.assertEqual(impulse_response_size, target_size)
def test_delay_compensation_corrects_group_delay(self, gain):
"""Test automatically compensating for group delay of linear phase filter.
Genearate filters to shift entire signal by a constant gain. Test that
filtered signal is in phase with original signal.
Args:
gain: Amount to scale the input signal.
"""
# Create random signal to filter.
output_np = gain * self.audio[0]
n_frequencies = 1025
window_size = 257
magnitudes = gain * tf.ones([1, n_frequencies], dtype=tf.float32)
impulse_response = core.frequency_impulse_response(
magnitudes, window_size)
output_tf = core.fft_convolve(self.audio,
impulse_response,
padding='same')[0]
difference = output_np - output_tf
total_difference = np.abs(difference).mean()
threshold = 1e-3
self.assertLessEqual(total_difference, threshold)