def trim_conditioning_sequence(self, start_frame: int, sequence_num_frames: int, target_num_frames: int):
        """
        Trim a conditioning sequence to the allowed number of frames.

        Args:
            start_frame (int): The target frame number of the first frame in the sequence.
            sequence_num_frames (int): The number of frames in the sequence.
            target_num_frames (int): The target number of frames in the generated video.
        Returns:
            int: updated sequence length
        """
        scale_factor = self.vae_temporal_compression_ratio
        num_frames = min(sequence_num_frames, target_num_frames - start_frame)
        # Trim down to a multiple of temporal_scale_factor frames plus 1
        num_frames = (num_frames - 1) // scale_factor * scale_factor + 1
        return num_frames

        Trim a conditioning sequence to the allowed number of frames.

        Args:
            start_frame (int): The target frame number of the first frame in the sequence.
            sequence_num_frames (int): The number of frames in the sequence.
            target_num_frames (int): The target number of frames in the generated video.
        Returns:
            int: updated sequence length
        
src/diffusers/pipelines/ltx/pipeline_ltx_condition.py