diff --git a/src/web/server.py b/src/web/server.py
index b394231..cb97400 100644
--- a/src/web/server.py
+++ b/src/web/server.py
@@ -15,7 +15,8 @@ import asyncio
 import json
 import os
 import logging
-import time
+import math
+import mimetypes
 import datetime
 from contextlib import asynccontextmanager
 from dataclasses import dataclass, field
@@ -1651,11 +1652,13 @@ class WebServer:
             "input_level": (
                 min(100, round((getattr(pl, '_input_level', 0.0) or 0.0) * 150))
                 if pl and isinstance(getattr(pl, '_input_level', None), (int, float))
+                and not math.isnan(getattr(pl, '_input_level', 0.0))
                 else 0
             ),
             "output_level": (
                 min(100, round((getattr(pl, '_output_level', 0.0) or 0.0) * 150))
                 if pl and isinstance(getattr(pl, '_output_level', None), (int, float))
+                and not math.isnan(getattr(pl, '_output_level', 0.0))
                 else 0
             ),
             # System stats