diff --git a/modules/demux/aiff.c b/modules/demux/aiff.c
index c4a50a1fed30987efd5424dc79f847a7efca69a5..e100cb41a171c72b9507475f589dee0376d24e7f 100644
--- a/modules/demux/aiff.c
+++ b/modules/demux/aiff.c
@@ -118,7 +118,7 @@ static int Open( vlc_object_t *p_this )
 
     /* Fill p_demux field */
     DEMUX_INIT_COMMON(); p_sys = p_demux->p_sys;
-    es_format_Init( &p_sys->fmt, UNKNOWN_ES, 0 );
+    es_format_Init( &p_sys->fmt, AUDIO_ES, 0 );
     p_sys->i_time = 0;
     p_sys->i_ssnd_pos = -1;