diff --git a/ffmpeg-definitions.rkt b/ffmpeg-definitions.rkt
index 5e02972..e2b11eb 100644
--- a/ffmpeg-definitions.rkt
+++ b/ffmpeg-definitions.rkt
@@ -488,8 +488,8 @@
 (define-syntax check-support
   (syntax-rules ()
     ((_ lib version-hash)
-     (let ((from (car (hash-ref lib version-hash)))
-           (until (cadr (hash-ref lib version-hash))))
+     (let ((from (car (hash-ref version-hash lib)))
+           (until (cadr (hash-ref version-hash lib))))
        (let ((major-version (car (ffmpeg-version lib))))
          (cond
            ((or (< major-version from) (> major-version until))