call__  < source > ( prompt: Union video_length: Optional = 8 height: Optional = None width: Optional = None num_inference_steps: int = 50 guidance_scale: float = 7.5 negative_prompt: Union = None num_videos_per_prompt: Optional = 1 eta: float = 0.0 generator: Union = None latents: Optional = None motion_field_strength_x: float = 12 motion_field_strength_y: float = 12 output_type: Optional = 'tensor' return_dict: bool = True callback: Optional 