Conv autoencoder, tiny set for testing.

def next_frame_ae_tiny():
  """Conv autoencoder, tiny set for testing."""
  hparams = next_frame_tiny()
  hparams.bottom["inputs"] = modalities.video_bitwise_bottom
  hparams.top["inputs"] = modalities.video_top
  hparams.batch_size = 8
  hparams.dropout = 0.4
  return hparams