def update(frames):
    if self.stream.is_active():
        slice = self.left.get_sample_slice(frames, frames + self.window)
        self.stream.write(slice.raw_data)
        y = np.array(slice.get_array_of_samples()) / 30000
        points = np.array([np.cos(time), y]).T.reshape((-1, 1, 2))  # 控制曲线精细程度和振幅
        segments = np.concatenate([points[:-1], points[1:]], axis=1)
        lc.set_segments(segments)
        lc.set_array(y)  # 控制颜色
    return lc,