diff --git a/removeads.py b/removeads.py
index 3629b80..a8f4e86 100755
--- a/removeads.py
+++ b/removeads.py
@@ -26,11 +26,15 @@ from shutil import copyfile, which
 
 def checkRequiredTools():
     logger = logging.getLogger(__name__)
-    tools = ['ffmpeg', 'ffprobe', 'mkvmerge']
-    for tool in tools:
+    required = ['ffmpeg', 'ffprobe', 'mkvmerge']
+    optional = ['mkvextract', 'vobusbocr']
+    for tool in required:
         if which(tool) == None:
             logger.error('Required tool: %s is missing.' % tool)
             exit(-1)
+    for tool in optional:
+        if which(tool) == None:
+            logger.info('Optional tool: %s is missing.' % tool)
 
 
 @unique