code: def _get_timebase_by_av_module(full_path):
      container = av.open(full_path)
      video_time_base = container.streams.video[0].time_base
      if container.streams.audio:
          audio_time_base = container.streams.audio[0].time_base
      else:
          audio_time_base = None
      return video_time_base, audio_time_base
  
imports: import collections
  import math
  import os
  from fractions import Fraction
  import numpy
  import pytest
  import torch
  import torchvision.io
  from common_utils import assert_equal
  from numpy.random import randint
  from pytest import approx
  from torchvision import set_video_backend
  from torchvision.io import _HAS_VIDEO_OPT
label_desc: Use image node_id 2 for calling a global function with example usage: _get_timebase_by_av_module(full_path) and returns: video_time_base,  audio_time_base