diff --git a/check-m4b b/check-m4b
new file mode 120000
index 0000000..ea58527
--- /dev/null
+++ b/check-m4b
@@ -0,0 +1 @@
+check-mp4
\ No newline at end of file
diff --git a/check-mp4 b/check-mp4
new file mode 100755
index 0000000..4f17e06
--- /dev/null
+++ b/check-mp4
@@ -0,0 +1,14 @@
+#!/bin/sh
+# check MP4 files by calling ffmpeg with the right options
+
+rc=0
+for mp4 in "$@"; do
+  echo -n "$mp4: "
+  if ffmpeg -v error -i "$mp4" -f null -; then
+    echo "OK"
+  else
+    echo "ERR"
+    rc=1
+  fi
+done
+exit $rc