def frame_function(self, t):
        """Renders a frame for the composition for the time ``t``."""
        played_parts = [clip.is_playing(t) for clip in self.clips]

        sounds = [
            clip.get_frame(t - clip.start) * np.array([part]).T
            for clip, part in zip(self.clips, played_parts)
            if (part is not False)
        ]

        if isinstance(t, np.ndarray):
            zero = np.zeros((len(t), self.nchannels))
        else:
            zero = np.zeros(self.nchannels)

        return zero + sum(sounds)
Renders a frame for the composition for the time ``t``.
moviepy/audio/AudioClip.py