demux: initialize the ES from the known category

Signed-off-by: Rémi Denis-Courmont <remi@remlab.net>

src/input/demux.c

@@ -514,7 +514,7 @@ decoder_t *demux_PacketizerNew( demux_t *p_demux, es_format_t *p_fmt, const char
     p_packetizer->pf_packetize = NULL;
 
     p_packetizer->fmt_in = *p_fmt;
-    es_format_Init( &p_packetizer->fmt_out, UNKNOWN_ES, 0 );
+    es_format_Init( &p_packetizer->fmt_out, p_fmt->i_cat, 0 );
 
     p_packetizer->p_module = module_need( p_packetizer, "packetizer", NULL, false );
     if( !p_packetizer->p_module )