diff --git a/scripts/led-matrix-viz.py b/scripts/led-matrix-viz.py
index 19d2dab..a67deca 100644
--- a/scripts/led-matrix-viz.py
+++ b/scripts/led-matrix-viz.py
@@ -104,10 +104,17 @@ def main():
                     pass
 
                 while b";" in buf:
-                    msg, buf = buf.split(b";", 1)
-                    msg = msg.decode().strip()
+                    raw_msg, buf = buf.split(b";", 1)
+                    msg = raw_msg.decode().strip()
                     parts = msg.split()
-                    if len(parts) >= 3 and parts[0] == "midi":
+                    if not parts:
+                        continue
+                    if parts[0] != "midi":
+                        print(f"[viz] skipping: {msg!r}", flush=True)
+                        continue
+                    if len(parts) < 3:
+                        print(f"[viz] too short: {parts}", flush=True)
+                        continue
                         status = int(parts[1])
                         note = int(parts[2])
                         vel = int(parts[3]) if len(parts) >= 4 else 0