MATROSKA_ID_TRACKENTRY  352 libavformat/matroskadec.c     { MATROSKA_ID_TRACKENTRY,         EBML_NEST, sizeof(MatroskaTrack), offsetof(MatroskaDemuxContext,tracks), {.n=matroska_track} },
MATROSKA_ID_TRACKENTRY  533 libavformat/matroskaenc.c         track = start_ebml_master(pb, MATROSKA_ID_TRACKENTRY, 0);