Mkv: use MKV_IS_ID and avoid EbmlId() operator use

modules/demux/mkv/demux.cpp

@@ -94,7 +94,7 @@ matroska_stream_c *demux_sys_t::AnalyseAllSegmentsFound( demux_t *p_demux, EbmlS
 
     while (p_l0 != 0)
     {
-        if (EbmlId(*p_l0) == KaxSegment::ClassInfos.GlobalId)
+        if ( MKV_IS_ID( p_l0, KaxSegment) )
         {
             EbmlParser  *ep;
             matroska_segment_c *p_segment1 = new matroska_segment_c( *this, *p_estream );

modules/demux/mkv/matroska_segment_parse.cpp

@@ -539,7 +539,7 @@ void matroska_segment_c::ParseTrackEntry( KaxTrackEntry *m )
                     tk->f_fps = float( vfps );
                     msg_Dbg( &sys.demuxer, "   |   |   |   + fps=%f", float( vfps ) );
                 }
-                else if( EbmlId( *l ) == KaxVideoDisplayUnit::ClassInfos.GlobalId )
+                else if( MKV_IS_ID( l, KaxVideoDisplayUnit ) )
                 {
                     KaxVideoDisplayUnit &vdmode = *(KaxVideoDisplayUnit*)l;