update trt dynamic shape for v3 rec

tools/infer/utility.py

@@ -271,7 +271,7 @@ def create_predictor(args, mode, logger):
             elif mode == "rec":
                 if args.rec_algorithm != "CRNN":
                     use_dynamic_shape = False
-                imgH = int(args.rec_image_shape.split(',')[1])
+                imgH = int(args.rec_image_shape.split(',')[-2])
                 min_input_shape = {"x": [1, 3, imgH, 10]}
                 max_input_shape = {"x": [args.rec_batch_num, 3, imgH, 1536]}
                 opt_input_shape = {"x": [args.rec_batch_num, 3, imgH, 320]}