def video_features(
      self, all_frames, all_actions, all_rewards, all_raw_frames):
    """Optional video wide features.

      If the model requires access to all of the video frames
      (e.g. in case of approximating one latent for the whole video)
      override this function to add them. They will be accessible
      as video_features in next_frame function.

    Args:
      all_frames: list of all frames including input and target frames.
      all_actions: list of all actions including input and target actions.
      all_rewards: list of all rewards including input and target rewards.
      all_raw_frames: list of all raw frames (before modalities).

    Returns:
      video_features: a dictionary containing video-wide features.
    """
    del all_frames, all_actions, all_rewards, all_raw_frames
    return None
Optional video wide features.

      If the model requires access to all of the video frames
      (e.g. in case of approximating one latent for the whole video)
      override this function to add them. They will be accessible
      as video_features in next_frame function.

    Args:
      all_frames: list of all frames including input and target frames.
      all_actions: list of all actions including input and target actions.
      all_rewards: list of all rewards including input and target rewards.
      all_raw_frames: list of all raw frames (before modalities).

    Returns:
      video_features: a dictionary containing video-wide features.
    
tensor2tensor/models/video/base.py