diff --git a/Av1an/chunk.py b/Av1an/chunk.py
index 25531f9..47fc5d4 100644
--- a/Av1an/chunk.py
+++ b/Av1an/chunk.py
@@ -36,7 +36,7 @@ class Chunk:
         self.temp: Path = temp
         self.frames: int = frames
         self.output_ext: str = output_ext
-        self.vmaf_target_cq = None
+        self.vmaf_target_cq: Optional[int] = None
 
     def to_dict(self) -> Dict[str, Any]:
         """