diff --git a/src/tscut/pipeline.py b/src/tscut/pipeline.py
index 8faddf2..791aaa2 100644
--- a/src/tscut/pipeline.py
+++ b/src/tscut/pipeline.py
@@ -8,7 +8,7 @@ from os import unlink
 from shutil import copyfile, move
 from sys import exit
 import logging
-from typing import IO, Any
+from typing import IO, Any, BinaryIO
 
 import hexdump
 
@@ -98,6 +98,8 @@ def process_recording(options: ProcessingOptions) -> None:
     if not found:
         logger.error('Unsupported format of file')
 
+    mkv: BinaryIO
+
     if final_format_of_file == SupportedFormat.TS:
         logger.info("Converting TS to MP4 (to fix timestamps).")
         try: