libavformat/oggdec.c:66: error: Null Dereference
  pointer `ost` last assigned on line 63 could be null and is dereferenced at line 66, column 5.

libavformat/oggdec.c:60:1: start of procedure ogg_save()
58. 
59. //FIXME We could avoid some structure duplication
60. static int ogg_save(AVFormatContext *s)
    ^
61. {
62.     struct ogg *ogg = s->priv_data;

libavformat/oggdec.c:62:5: 
60. static int ogg_save(AVFormatContext *s)
61. {
62.     struct ogg *ogg = s->priv_data;
        ^
63.     struct ogg_state *ost =
64.         av_malloc(sizeof (*ost) + (ogg->nstreams-1) * sizeof (*ogg->streams));

libavformat/oggdec.c:63:5: 
61. {
62.     struct ogg *ogg = s->priv_data;
63.     struct ogg_state *ost =
        ^
64.         av_malloc(sizeof (*ost) + (ogg->nstreams-1) * sizeof (*ogg->streams));
65.     int i;

libavutil/mem.c:64:1: start of procedure av_malloc()
  62.    linker will do it automatically. */
  63. 
  64. void *av_malloc(size_t size)
      ^
  65. {
  66.     void *ptr = NULL;

libavutil/mem.c:66:5: 
  64. void *av_malloc(size_t size)
  65. {
  66.     void *ptr = NULL;
          ^
  67. #if CONFIG_MEMALIGN_HACK
  68.     long diff;

libavutil/mem.c:72:8: Taking false branch
  70. 
  71.     /* let's disallow possible ambiguous cases */
  72.     if(size > (INT_MAX-32) )
             ^
  73.         return NULL;
  74. 

libavutil/mem.c:83:9: Taking true branch
  81.     ((char*)ptr)[-1]= diff;
  82. #elif HAVE_POSIX_MEMALIGN
  83.     if (posix_memalign(&ptr,32,size))
              ^
  84.         ptr = NULL;
  85. #elif HAVE_MEMALIGN

libavutil/mem.c:84:9: 
  82. #elif HAVE_POSIX_MEMALIGN
  83.     if (posix_memalign(&ptr,32,size))
  84.         ptr = NULL;
              ^
  85. #elif HAVE_MEMALIGN
  86.     ptr = memalign(32,size);

libavutil/mem.c:114:5: 
  112.     ptr = malloc(size);
  113. #endif
  114.     return ptr;
           ^
  115. }
  116. 

libavutil/mem.c:115:1: return from a call to av_malloc
  113. #endif
  114.     return ptr;
  115. }
       ^
  116. 
  117. void *av_realloc(void *ptr, size_t size)

libavformat/oggdec.c:66:5: 
64.         av_malloc(sizeof (*ost) + (ogg->nstreams-1) * sizeof (*ogg->streams));
65.     int i;
66.     ost->pos = avio_tell (s->pb);
        ^
67.     ost->curidx = ogg->curidx;
68.     ost->next = ogg->state;

libavformat/avio.h:450:1: start of procedure avio_tell()
  448.  * @return position or AVERROR.
  449.  */
  450. static av_always_inline int64_t avio_tell(AVIOContext *s)
       ^
  451. {
  452.     return avio_seek(s, 0, SEEK_CUR);

libavformat/avio.h:452:5: Skipping avio_seek(): empty list of specs
  450. static av_always_inline int64_t avio_tell(AVIOContext *s)
  451. {
  452.     return avio_seek(s, 0, SEEK_CUR);
           ^
  453. }
  454. 

libavformat/avio.h:453:1: return from a call to avio_tell
  451. {
  452.     return avio_seek(s, 0, SEEK_CUR);
  453. }
       ^
  454. 
  455. /**
