libavcodec/utils.c:870: error: Null Dereference
  pointer `desc` last assigned on line 869 could be null and is dereferenced at line 870, column 12.

libavcodec/utils.c:867:1: start of procedure is_hwaccel_pix_fmt()
865. }
866. 
867. static int is_hwaccel_pix_fmt(enum AVPixelFormat pix_fmt)
     ^
868. {
869.     const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(pix_fmt);

libavcodec/utils.c:869:5: 
867. static int is_hwaccel_pix_fmt(enum AVPixelFormat pix_fmt)
868. {
869.     const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(pix_fmt);
         ^
870.     return desc->flags & AV_PIX_FMT_FLAG_HWACCEL;
871. }

libavutil/pixdesc.c:1599:1: start of procedure av_pix_fmt_desc_get()
  1597. }
  1598. 
  1599. const AVPixFmtDescriptor *av_pix_fmt_desc_get(enum AVPixelFormat pix_fmt)
        ^
  1600. {
  1601.     if (pix_fmt < 0 || pix_fmt >= AV_PIX_FMT_NB)

libavutil/pixdesc.c:1601:9: Taking false branch
  1599. const AVPixFmtDescriptor *av_pix_fmt_desc_get(enum AVPixelFormat pix_fmt)
  1600. {
  1601.     if (pix_fmt < 0 || pix_fmt >= AV_PIX_FMT_NB)
                ^
  1602.         return NULL;
  1603.     return &av_pix_fmt_descriptors[pix_fmt];

libavutil/pixdesc.c:1601:24: Taking true branch
  1599. const AVPixFmtDescriptor *av_pix_fmt_desc_get(enum AVPixelFormat pix_fmt)
  1600. {
  1601.     if (pix_fmt < 0 || pix_fmt >= AV_PIX_FMT_NB)
                               ^
  1602.         return NULL;
  1603.     return &av_pix_fmt_descriptors[pix_fmt];

libavutil/pixdesc.c:1602:9: 
  1600. {
  1601.     if (pix_fmt < 0 || pix_fmt >= AV_PIX_FMT_NB)
  1602.         return NULL;
                ^
  1603.     return &av_pix_fmt_descriptors[pix_fmt];
  1604. }

libavutil/pixdesc.c:1604:1: return from a call to av_pix_fmt_desc_get
  1602.         return NULL;
  1603.     return &av_pix_fmt_descriptors[pix_fmt];
  1604. }
        ^
  1605. 
  1606. const AVPixFmtDescriptor *av_pix_fmt_desc_next(const AVPixFmtDescriptor *prev)

libavcodec/utils.c:870:5: 
868. {
869.     const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(pix_fmt);
870.     return desc->flags & AV_PIX_FMT_FLAG_HWACCEL;
         ^
871. }
872. 
