diff --git a/wrappers/ffmpeg.sh b/wrappers/ffmpeg.sh
index a000082..5b989c7 100644
--- a/wrappers/ffmpeg.sh
+++ b/wrappers/ffmpeg.sh
@@ -73,7 +73,7 @@ fix_args() {
           scale_w=$(echo "$arg" | sed -e 's/.*=w=//g' | sed -e 's/:h=.*//g')
           # shellcheck disable=SC2001
           scale_h=$(echo "$arg" | sed -e 's/.*:h=//g')
-          if [[ "$scale_w" != "" && "$scale_h" != "" ]]; then
+          if (( scale_w && scale_h )); then
             arg="scale_vaapi=w=$scale_w:h=$scale_h:format=nv12,hwupload,setsar=sar=1"
           else
             arg="scale_vaapi=format=nv12,hwupload,setsar=sar=1"