import numpy as np
from moviepy.decorators import audio_video_fx, convert_parameter_to_seconds
def _multiply_volume_in_range(factor, start_time, end_time, nchannels):
def factors_filter(factor, t):
return np.array([factor if start_time <= t_ <= end_time else 1 for t_ in t])
def multiply_stereo_volume(get_frame, t):
return np.multiply(
get_frame(t),
np.array([factors_filter(factor, t) for _ in range(nchannels)]).T,
)
def multiply_mono_volume(get_frame, t):
return np.multiply(get_frame(t), factors_filter(factor, t))
return multiply_mono_volume if nchannels == 1 else multiply_stereo_volume
[docs]@audio_video_fx
@convert_parameter_to_seconds(["start_time", "end_time"])
def multiply_volume(clip, factor, start_time=None, end_time=None):
"""Returns a clip with audio volume multiplied by the
value `factor`. Can be applied to both audio and video clips.
Parameters
----------
factor : float
Volume multiplication factor.
start_time : float, optional
Time from the beginning of the clip until the volume transformation
begins to take effect, in seconds. By default at the beginning.
end_time : float, optional
Time from the beginning of the clip until the volume transformation
ends to take effect, in seconds. By default at the end.
Examples
--------
>>> from moviepy import AudioFileClip
>>>
>>> music = AudioFileClip('music.ogg')
>>> doubled_audio_clip = clip.multiply_volume(2) # doubles audio volume
>>> half_audio_clip = clip.multiply_volume(0.5) # half audio
>>>
>>> # silenced clip during one second at third
>>> silenced_clip = clip.multiply_volume(0, start_time=2, end_time=3)
"""
if start_time is None and end_time is None:
return clip.transform(
lambda get_frame, t: factor * get_frame(t),
keep_duration=True,
)
return clip.transform(
_multiply_volume_in_range(
factor,
clip.start if start_time is None else start_time,
clip.end if end_time is None else end_time,
clip.nchannels,
),
keep_duration=True,
)