code: def _create_video_frames(num_frames, height, width):
      y, x = torch.meshgrid(
          torch.linspace(-2, 2, height),
          torch.linspace(-2, 2, width),
          indexing="ij",
      )
      data = []
      for i in range(num_frames):
          xc = float(i) / num_frames
          yc = 1 - float(i) / (2 * num_frames)
          d = torch.exp(-((x - xc) ** 2 + (y - yc) ** 2) / 2) * 255
          data.append(d.unsqueeze(2).repeat(1, 1, 3).byte())
  
      return torch.stack(data, 0)
  
imports: import contextlib
  import os
  import sys
  import tempfile
  import pytest
  import torch
  import torchvision.io
  from common_utils import assert_equal
  from torchvision import get_video_backend
label_desc: Use image node_id 1 for calling a global function with example usage: _create_video_frames(num_frames, height, width) and returns: torch