diff --git a/build-ffmpeg.sh b/build-ffmpeg.sh
old mode 100755
new mode 100644
index df47d8b..1eb3786
--- a/build-ffmpeg.sh
+++ b/build-ffmpeg.sh
@@ -116,6 +116,7 @@ CONFIGURE_ARGS=(
     --disable-encoders
     --enable-encoder=mjpeg
     --disable-muxers
+    --enable-muxer=spdif
     --enable-gpl
     --enable-libass
     --enable-libdav1d
@@ -142,6 +143,11 @@ if ! ./configure "${CONFIGURE_ARGS[@]}"; then
     exit 1
 fi
 
+if ! grep -Eq '^#define CONFIG_SPDIF_MUXER 1$' config_components.h; then
+    echo "FFmpeg spdif muxer is required for mpv audio passthrough" >&2
+    exit 1
+fi
+
 echo "Building FFmpeg with jobs=$FFMPEG_JOBS"
 make -j"$FFMPEG_JOBS"
 make install