diff --git a/aoirint_matvtool/blank_video.py b/aoirint_matvtool/blank_video.py
new file mode 100644
index 0000000..e2e8dae
--- /dev/null
+++ b/aoirint_matvtool/blank_video.py
@@ -0,0 +1,19 @@
+from pathlib import Path
+from typing import Iterable, Optional, Union
+
+from pydantic import BaseModel
+
+from .find_image import FfmpegProgressLine
+
+
+class FfmpegBlankVideoResult(BaseModel):
+    success: bool
+    message: Optional[str]
+
+
+def ffmpeg_blank_video(
+    input_path: Path,
+    duration_seconds: Optional[str],
+    output_path: Path,
+) -> Iterable[Union[FfmpegBlankVideoResult, FfmpegProgressLine]]:
+    raise Exception("WIP")