diff --git a/build.sh b/build.sh
index 98a083b..d6ddfcb 100755
--- a/build.sh
+++ b/build.sh
@@ -18,6 +18,8 @@ get_output() {
 source "variants/${VARIANT}.sh"
 source "variants/${TARGET}-${VARIANT}.sh"
 
+export FFBUILD_PREFIX="$(docker run --rm btbn/ffmpeg-builder:win64-gpl bash -c 'echo $FFBUILD_PREFIX')"
+
 for script in scripts.d/*.sh; do
     FF_CONFIGURE+=" $(get_output $script configure)"
     FF_CFLAGS+=" $(get_output $script cflags)"