diff --git a/gnes/preprocessor/io_utils/video.py b/gnes/preprocessor/io_utils/video.py
index ef54a9e3..21238dea 100644
--- a/gnes/preprocessor/io_utils/video.py
+++ b/gnes/preprocessor/io_utils/video.py
@@ -54,10 +54,12 @@ def scale_video(input_filename: str = 'pipe:',
         'vcodec': vcodec,
         'pix_fmt': pix_fmt,
         'crf': crf,
-        's': scale,
         'framerate': frame_rate
     }
 
+    if scale:
+        out_kwargs['s'] = scale
+
     if capture_stdout:
         out_kwargs['format'] = format
         # an empty moov means it doesn't need to seek and thus works with a pipe.