docs: async def recv(self):
          """
          Receive the next :class:`~av.video.frame.VideoFrame`.
  
          The base implementation just reads a 640x480 green frame at 30fps,
          subclass :class:`VideoStreamTrack` to provide a useful implementation.
          """
          pts, time_base = await self.next_timestamp()
  
          frame = VideoFrame(width=640, height=480)
          for p in frame.planes:
              p.update(bytes(p.buffer_size))
          frame.pts = pts
          frame.time_base = time_base
          return frame