initial commit and version 1.0

moviepy/audio/fx/MultiplyStereoVolume.py

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+from dataclasses import dataclass
+
+from moviepy.Clip import Clip
+from moviepy.decorators import audio_video_effect
+from moviepy.Effect import Effect
+
+
+@dataclass
+class MultiplyStereoVolume(Effect):
+    """For a stereo audioclip, this function enables to change the volume
+    of the left and right channel separately (with the factors `left`
+    and `right`). Makes a stereo audio clip in which the volume of left
+    and right is controllable.
+
+    Examples
+    --------
+
+    .. code:: python
+
+        from moviepy import AudioFileClip
+        music = AudioFileClip('music.ogg')
+        # mutes left channel
+        audio_r = music.with_effects([afx.MultiplyStereoVolume(left=0, right=1)])
+        # halves audio volume
+        audio_h = music.with_effects([afx.MultiplyStereoVolume(left=0.5, right=0.5)])
+    """
+
+    left: float = 1
+    right: float = 1
+
+    @audio_video_effect
+    def apply(self, clip: Clip) -> Clip:
+        """Apply the effect to the clip."""
+
+        def stereo_volume(get_frame, t):
+            frame = get_frame(t)
+            if len(frame) == 1:  # mono
+                frame *= self.left if self.left is not None else self.right
+            else:  # stereo, stereo surround...
+                for i in range(len(frame[0])):  # odd channels are left
+                    frame[:, i] *= self.left if i % 2 == 0 else self.right
+            return frame
+
+        return clip.transform(stereo_volume)