def test_multiply_volume():
clip = AudioFileClip("media/crunching.mp3")
clip_array = clip.to_soundarray()
# stereo mute
clip_muted = multiply_volume(clip, 0)
left_channel_muted = clip_muted.to_soundarray()[:, 0]
right_channel_muted = clip_muted.to_soundarray()[:, 1]
z_channel = np.zeros(len(left_channel_muted))
assert np.array_equal(left_channel_muted, z_channel)
assert np.array_equal(right_channel_muted, z_channel)
# stereo level doubled
clip_doubled = multiply_volume(clip, 2)
clip_doubled_array = clip_doubled.to_soundarray()
left_channel_doubled = clip_doubled_array[:, 0]
right_channel_doubled = clip_doubled_array[:, 1]
expected_left_channel_doubled = clip_array[:, 0] * 2
expected_right_channel_doubled = clip_array[:, 1] * 2
assert np.array_equal(left_channel_doubled, expected_left_channel_doubled)
assert np.array_equal(right_channel_doubled,
expected_right_channel_doubled)
# mono muted
sinus_wave = lambda t: [np.sin(440 * 2 * np.pi * t)]
mono_clip = AudioClip(sinus_wave, duration=1, fps=22050)
muted_mono_clip = multiply_volume(mono_clip, 0)
mono_channel_muted = muted_mono_clip.to_soundarray()
z_channel = np.zeros(len(mono_channel_muted))
assert np.array_equal(mono_channel_muted, z_channel)
mono_clip = AudioClip(sinus_wave, duration=1, fps=22050)
doubled_mono_clip = multiply_volume(mono_clip, 2)
mono_channel_doubled = doubled_mono_clip.to_soundarray()
d_channel = mono_clip.to_soundarray() * 2
assert np.array_equal(mono_channel_doubled, d_channel)
close_all_clips(locals())
def test_multiply_stereo_volume():
clip = AudioFileClip("media/crunching.mp3")
# mute
clip_left_channel_muted = multiply_stereo_volume(clip, left=0)
clip_right_channel_muted = multiply_stereo_volume(clip, right=0, left=2)
left_channel_muted = clip_left_channel_muted.to_soundarray()[:, 0]
right_channel_muted = clip_right_channel_muted.to_soundarray()[:, 1]
z_channel = np.zeros(len(left_channel_muted))
assert np.array_equal(left_channel_muted, z_channel)
assert np.array_equal(right_channel_muted, z_channel)
# double level
left_channel_doubled = clip_right_channel_muted.to_soundarray()[:, 0]
d_channel = clip.to_soundarray()[:, 0] * 2
assert np.array_equal(left_channel_doubled, d_channel)
# mono muted
sinus_wave = lambda t: [np.sin(440 * 2 * np.pi * t)]
mono_clip = AudioClip(sinus_wave, duration=2, fps=22050)
muted_mono_clip = multiply_stereo_volume(mono_clip, left=0)
mono_channel_muted = muted_mono_clip.to_soundarray()
z_channel = np.zeros(len(mono_channel_muted))
assert np.array_equal(mono_channel_muted, z_channel)
# mono doubled
mono_clip = AudioClip(sinus_wave, duration=2, fps=22050)
doubled_mono_clip = multiply_stereo_volume(
mono_clip, left=None, right=2
) # using right
mono_channel_doubled = doubled_mono_clip.to_soundarray()
d_channel = mono_clip.to_soundarray() * 2
assert np.array_equal(mono_channel_doubled, d_channel)
close_all_clips(locals())
