libavformat/matroskadec.c:1987: error: Buffer Overrun L2
  Offset: [-oo, max(16, `matroska->num_levels`)] Size: 16.

libavformat/matroskadec.c:1851:1: <Offset trace>
1849. }
1850. 
1851. static int
      ^
1852. matroska_parse_seekhead (MatroskaDemuxContext *matroska)
1853. {

libavformat/matroskadec.c:1851:1: Parameter `matroska->num_levels`
1849. }
1850. 
1851. static int
      ^
1852. matroska_parse_seekhead (MatroskaDemuxContext *matroska)
1853. {

libavformat/matroskadec.c:1860:20: Call
1858. 
1859.     while (res == 0) {
1860.         if (!(id = ebml_peek_id(matroska, &matroska->level_up))) {
                         ^
1861.             res = AVERROR(EIO);
1862.             break;

libavformat/matroskadec.c:318:1: Parameter `matroska->num_levels`
  316.  */
  317. 
  318. static uint32_t
       ^
  319. ebml_peek_id (MatroskaDemuxContext *matroska,
  320.               int                  *level_up)

libavformat/matroskadec.c:324:9: Call
  322.     uint32_t id;
  323. 
  324.     if (ebml_read_element_id(matroska, &id, level_up) < 0)
               ^
  325.         return 0;
  326. 

libavformat/matroskadec.c:268:1: Parameter `matroska->num_levels`
    266.  */
    267. 
    268. static int
         ^
    269. ebml_read_element_id (MatroskaDemuxContext *matroska,
    270.                       uint32_t             *id,

libavformat/matroskadec.c:1873:28: Call
1871.                 uint64_t seek_pos = (uint64_t) -1, t;
1872. 
1873.                 if ((res = ebml_read_master(matroska, &id)) < 0)
                                 ^
1874.                     break;
1875. 

libavformat/matroskadec.c:544:1: Parameter `matroska->num_levels`
  542.  */
  543. 
  544. static int
       ^
  545. ebml_read_master (MatroskaDemuxContext *matroska,
  546.                   uint32_t             *id)

libavformat/matroskadec.c:553:16: Call
  551.     int res;
  552. 
  553.     if ((res = ebml_read_element_id(matroska, id, NULL)) < 0 ||
                      ^
  554.         (res = ebml_read_element_length(matroska, &length)) < 0)
  555.         return res;

libavformat/matroskadec.c:268:1: Parameter `matroska->num_levels`
    266.  */
    267. 
    268. static int
         ^
    269. ebml_read_element_id (MatroskaDemuxContext *matroska,
    270.                       uint32_t             *id,

libavformat/matroskadec.c:1985:29: Assignment
1983.                         /* remove dummy level */
1984.                         while (matroska->num_levels) {
1985.                             matroska->num_levels--;
                                  ^
1986.                             length =
1987.                                 matroska->levels[matroska->num_levels].length;

libavformat/matroskadec.c:1851:1: <Length trace>
1849. }
1850. 
1851. static int
      ^
1852. matroska_parse_seekhead (MatroskaDemuxContext *matroska)
1853. {

libavformat/matroskadec.c:1851:1: Parameter `matroska->levels[*]`
1849. }
1850. 
1851. static int
      ^
1852. matroska_parse_seekhead (MatroskaDemuxContext *matroska)
1853. {

libavformat/matroskadec.c:1987:33: Array access: Offset: [-oo, max(16, matroska->num_levels)] Size: 16
1985.                             matroska->num_levels--;
1986.                             length =
1987.                                 matroska->levels[matroska->num_levels].length;
                                      ^
1988.                             if (length == (uint64_t)-1)
1989.                                 break;
