Do not require preprocess_resize_frames in hparams for VideoProblem

PiperOrigin-RevId: 207295010

tensor2tensor/data_generators/video_utils.py

@@ -140,7 +140,7 @@ def use_not_breaking_batching(self):
 
   def preprocess_example(self, example, mode, hparams):
     """Runtime preprocessing, e.g., resize example["frame"]."""
-    if hparams.preprocess_resize_frames is not None:
+    if getattr(hparams, "preprocess_resize_frames", None) is not None:
       example["frame"] = tf.image.resize_images(
           example["frame"],
           hparams.preprocess_resize_frames,