Add missing SPDX header

Author: Josh5

lib/smart_black_bar_detect.py

@@ -1,3 +1,27 @@
+#!/usr/bin/env python3
+# -*- coding: utf-8 -*-
+
+"""
+    plugins.nvenc.py
+
+    Written by:               Josh.5 <jsunnex@gmail.com>
+    Date:                     16 Dec 2025, (09:36 AM)
+
+    Copyright:
+        Copyright (C) 2021 Josh Sunnex
+
+        This program is free software: you can redistribute it and/or modify it under the terms of the GNU General
+        Public License as published by the Free Software Foundation, version 3.
+
+        This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the
+        implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+        for more details.
+
+        You should have received a copy of the GNU General Public License along with this program.
+        If not, see <https://www.gnu.org/licenses/>.
+
+"""
+
 import logging
 import re
 import subprocess