initial commit and version 1.0

moviepy/audio/fx/AudioDelay.py

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+from dataclasses import dataclass
+
+import numpy as np
+
+from moviepy.audio.AudioClip import CompositeAudioClip
+from moviepy.audio.fx.MultiplyVolume import MultiplyVolume
+from moviepy.Clip import Clip
+from moviepy.decorators import audio_video_effect
+from moviepy.Effect import Effect
+
+
+@dataclass
+class AudioDelay(Effect):
+    """Repeats audio certain number of times at constant intervals multiplying
+    their volume levels using a linear space in the range 1 to ``decay`` argument
+    value.
+
+    Parameters
+    ----------
+
+    offset : float, optional
+      Gap between repetitions start times, in seconds.
+
+    n_repeats : int, optional
+      Number of repetitions (without including the clip itself).
+
+    decay : float, optional
+      Multiplication factor for the volume level of the last repetition. Each
+      repetition will have a value in the linear function between 1 and this value,
+      increasing or decreasing constantly. Keep in mind that the last repetition
+      will be muted if this is 0, and if is greater than 1, the volume will increase
+      for each repetition.
+
+    Examples
+    --------
+
+    .. code:: python
+
+        from moviepy import *
+        videoclip = AudioFileClip('myaudio.wav').with_effects([
+            afx.AudioDelay(offset=.2, n_repeats=10, decayment=.2)
+        ])
+
+        # stereo A note
+        frame_function = lambda t: np.array(
+            [np.sin(440 * 2 * np.pi * t), np.sin(880 * 2 * np.pi * t)]
+        ).T
+        clip = AudioClip(frame_function=frame_function, duration=0.1, fps=44100)
+        clip = clip.with_effects([afx.AudioDelay(offset=.2, n_repeats=11, decay=0)])
+    """
+
+    offset: float = 0.2
+    n_repeats: int = 8
+    decay: float = 1
+
+    @audio_video_effect
+    def apply(self, clip: Clip) -> Clip:
+        """Apply the effect to the clip."""
+        decayments = np.linspace(1, max(0, self.decay), self.n_repeats + 1)
+        return CompositeAudioClip(
+            [
+                clip.copy(),
+                *[
+                    clip.with_start((rep + 1) * self.offset).with_effects(
+                        [MultiplyVolume(decayments[rep + 1])]
+                    )
+                    for rep in range(self.n_repeats)
+                ],
+            ]
+        )