Minor fixes

app.py

@@ -159,8 +159,14 @@ def process(
     info = f"""
     Wave duration  : {duration: .3f} s <br/>
     Processing time: {end - start: .3f} s <br/>
-    RTF: {end - start: .3f}/{duration: .3f} = {(end - start)/duration:.3f} <br/>
+    RTF: {end - start: .3f}/{duration: .3f} = {rtf:.3f} <br/>
     """
+    if rtf > 1:
+        info += (
+            f"<br/>We are loading the model for the first run. "
+            "Please run again to measure the real RTF.<br/>"
+        )
+
     logging.info(info)
     logging.info(f"hyp:\n{hyp}")