libavformat/oggdec.c:65: error: Null Dereference
  pointer `ost` last assigned on line 62 could be null and is dereferenced at line 65, column 5.

libavformat/oggdec.c:58:1: start of procedure ogg_save()
56. 
57. //FIXME We could avoid some structure duplication
58. static int
    ^
59. ogg_save (AVFormatContext * s)
60. {

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

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

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

libavutil/mem.c:66:5: 
  64. void *av_malloc(unsigned int 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-16) )
             ^
  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,16,size))
              ^
  84.         ptr = NULL;
  85. #elif HAVE_MEMALIGN

libavutil/mem.c:84:9: 
  82. #elif HAVE_POSIX_MEMALIGN
  83.     if (posix_memalign(&ptr,16,size))
  84.         ptr = NULL;
              ^
  85. #elif HAVE_MEMALIGN
  86.     ptr = memalign(16,size);

libavutil/mem.c:116:5: 
  114.     ptr = malloc(size);
  115. #endif
  116.     return ptr;
           ^
  117. }
  118. 

libavutil/mem.c:117:1: return from a call to av_malloc
  115. #endif
  116.     return ptr;
  117. }
       ^
  118. 
  119. void *av_realloc(void *ptr, unsigned int size)

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

libavformat/aviobuf.c:186:1: start of procedure url_ftell()
  184. }
  185. 
  186. int64_t url_ftell(ByteIOContext *s)
       ^
  187. {
  188.     return url_fseek(s, 0, SEEK_CUR);

libavformat/aviobuf.c:188:5: Skipping url_fseek(): empty list of specs
  186. int64_t url_ftell(ByteIOContext *s)
  187. {
  188.     return url_fseek(s, 0, SEEK_CUR);
           ^
  189. }
  190. 

libavformat/aviobuf.c:189:1: return from a call to url_ftell
  187. {
  188.     return url_fseek(s, 0, SEEK_CUR);
  189. }
       ^
  190. 
  191. int64_t url_fsize(ByteIOContext *s)
