diff --git a/webmenc.h b/webmenc.h
index 0ac606b..c255d3d 100644
--- a/webmenc.h
+++ b/webmenc.h
@@ -42,7 +42,8 @@
                             const vpx_codec_enc_cfg_t *cfg,
                             const struct vpx_rational *fps,
                             stereo_format_t stereo_fmt,
-                            unsigned int fourcc);
+                            unsigned int fourcc,
+                            const struct VpxRational *par);
 
 void write_webm_block(struct EbmlGlobal *glob,
                       const vpx_codec_enc_cfg_t *cfg,