code: def _get_vfilter_desc(
      frame_rate: Optional[float],
      width: Optional[int],
      height: Optional[int],
      fmt: Optional[str],
  ):
      descs = []
      if frame_rate is not None:
          descs.append(f"fps={frame_rate}")
      scales = []
      if width is not None:
          scales.append(f"width={width}")
      if height is not None:
          scales.append(f"height={height}")
      if scales:
          descs.append(f"scale={':'.join(scales)}")
      if fmt is not None:
          descs.append(f"format=pix_fmts={fmt}")
      return ",".join(descs) if descs else None
  
imports: from __future__ import annotations
  import os
  from dataclasses import dataclass
  from pathlib import Path
  from typing import BinaryIO, Dict, Iterator, Optional, Tuple, TypeVar, Union
  import torch
  import torio
  from torch.utils._pytree import tree_map
label_desc: Use image node_id 4 for calling a global function with example usage: _get_vfilter_desc(frame_rate, width, height, fmt) and returns: unknown