Make filter count zero after releasing all audio filters.

modules/stream_out/transcode.c

@@ -1535,6 +1535,7 @@ static void transcode_audio_close( sout_stream_t *p_stream,
         vlc_object_destroy( id->pp_filter[i] );
         id->pp_filter[i] = NULL;
     }
+    id->i_filter = 0;
 
     for( i = 0; i < id->i_ufilter; i++ )
     {
@@ -1544,6 +1545,7 @@ static void transcode_audio_close( sout_stream_t *p_stream,
         vlc_object_destroy( id->pp_ufilter[i] );
         id->pp_ufilter[i] = NULL;
     }
+    id->i_ufilter = 0;
 }
 
 static int transcode_audio_process( sout_stream_t *p_stream,