diff --git a/modules/demux/smf.c b/modules/demux/smf.c
index baaf5aebb475e9b04ee17546a9c4ffe7401dd70f..2785cec366009b88920f2e9ecb83b33ef7d2ef29 100644
--- a/modules/demux/smf.c
+++ b/modules/demux/smf.c
@@ -231,6 +231,10 @@ static int Open (vlc_object_t * p_this)
 
     es_format_t  fmt;
     es_format_Init (&fmt, AUDIO_ES, VLC_FOURCC('M', 'I', 'D', 'I'));
+    fmt.audio.i_channels = 2;
+    fmt.audio.i_original_channels = fmt.audio.i_physical_channels =
+        AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT;
+    fmt.audio.i_rate = 44100; /* dummy value */
     p_sys->es = es_out_Add (p_demux->out, &fmt);
 
     return VLC_SUCCESS;