diff --git a/automation/vapoursynth/aegisub_vs.py b/automation/vapoursynth/aegisub_vs.py
index dc354df03c..7de104ddcb 100644
--- a/automation/vapoursynth/aegisub_vs.py
+++ b/automation/vapoursynth/aegisub_vs.py
@@ -236,7 +236,7 @@ def _cb(n: int, f: vs.VideoFrame) -> vs.VideoFrame:
         nonlocal done
         keyframes[n] = f.props._SceneChangePrev if use_scxvid else f.props.Scenechange # type: ignore
         done += 1
-        if done % (clip.num_frames // 200) == 0:
+        if done % max(1, clip.num_frames // 200) == 0:
             progress_set_progress(100 * done / clip.num_frames)
         return f