del for video-like data.  forward  < source > ( hidden_states: FloatTensor encoder_hidden_states: Optional = None timestep: Optional = None class_labels: LongTensor = None num_frames: int = 1 cross_attention_kwargs: Optional = None return_dict: bool = True  ) → TransformerTemporalModelOutput or tuple  Parameters   hidden_states (torch.LongTensor of shape (batch size, num latent pixels) if discrete, torch.FloatTensor of shape (batch size, channe