diff --git a/ffmpeg-myth.scm b/ffmpeg-myth.scm
index 7bca51b..77f9ebb 100755
--- a/ffmpeg-myth.scm
+++ b/ffmpeg-myth.scm
@@ -193,8 +193,10 @@
 		 (cl (cddr l) (if (< (caar l) (caadr l)) (append (list (cons (caar l) (caadr l))) acc) acc)))
 		(#t
 		 (cl (cdr l) acc)))))
-    (if (and (start-of-cut? (cadar s)) (> (caar s) 0))
-	(set! s (append '((0 0)) s)))
+    (cond ((null? s)
+	   (set! s '((0 0))))
+	  ((and (start-of-cut? (cadar s)) (> (caar s) 0))
+	   (set! s (append '((0 0)) s))))
     (if (end-of-cut?   (cadr (last s)))
 	(set! s (append s (list (list (if (null? f) (greatest-fixnum) (caar f)) 1)))))
     (set! s (map (lambda(x) (if (start-of-cut? (cadr x)) (cons (car x) start) (cons (car x) end)))