diff --git a/entity/ffmpeg.py b/entity/ffmpeg.py
index ef9e19e..1079991 100644
--- a/entity/ffmpeg.py
+++ b/entity/ffmpeg.py
@@ -148,7 +148,7 @@ class FfmpegTask(object):
                 input_index = input_args.count("-i")
                 input_args.append("-i")
                 input_args.append(overlay)
-                filter_args.append(f"{video_output_str}[{input_index}:v]scale=rw:rh[v]")
+                filter_args.append(f"{video_output_str}[{input_index}:v]scale2ref=mw:mh[v]")
                 filter_args.append(f"[v][{input_index}:v]overlay=1:eof_action=endall[v]")
                 video_output_str = "[v]"
             for subtitle in self.subtitles: