libavcodec/hevc.c:2768: error: Null Dereference
  pointer `desc` last assigned on line 2767 could be null and is dereferenced at line 2768, column 23.

libavcodec/hevc.c:2765:1: start of procedure verify_md5()
2763. }
2764. 
2765. static int verify_md5(HEVCContext *s, AVFrame *frame)
      ^
2766. {
2767.     const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(frame->format);

libavcodec/hevc.c:2767:5: 
2765. static int verify_md5(HEVCContext *s, AVFrame *frame)
2766. {
2767.     const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(frame->format);
          ^
2768.     int pixel_shift = desc->comp[0].depth_minus1 > 7;
2769.     int i, j;

libavutil/pixdesc.c:1507:1: start of procedure av_pix_fmt_desc_get()
  1505. }
  1506. 
  1507. const AVPixFmtDescriptor *av_pix_fmt_desc_get(enum AVPixelFormat pix_fmt)
        ^
  1508. {
  1509.     if (pix_fmt < 0 || pix_fmt >= AV_PIX_FMT_NB)

libavutil/pixdesc.c:1509:9: Taking false branch
  1507. const AVPixFmtDescriptor *av_pix_fmt_desc_get(enum AVPixelFormat pix_fmt)
  1508. {
  1509.     if (pix_fmt < 0 || pix_fmt >= AV_PIX_FMT_NB)
                ^
  1510.         return NULL;
  1511.     return &av_pix_fmt_descriptors[pix_fmt];

libavutil/pixdesc.c:1509:24: Taking true branch
  1507. const AVPixFmtDescriptor *av_pix_fmt_desc_get(enum AVPixelFormat pix_fmt)
  1508. {
  1509.     if (pix_fmt < 0 || pix_fmt >= AV_PIX_FMT_NB)
                               ^
  1510.         return NULL;
  1511.     return &av_pix_fmt_descriptors[pix_fmt];

libavutil/pixdesc.c:1510:9: 
  1508. {
  1509.     if (pix_fmt < 0 || pix_fmt >= AV_PIX_FMT_NB)
  1510.         return NULL;
                ^
  1511.     return &av_pix_fmt_descriptors[pix_fmt];
  1512. }

libavutil/pixdesc.c:1512:1: return from a call to av_pix_fmt_desc_get
  1510.         return NULL;
  1511.     return &av_pix_fmt_descriptors[pix_fmt];
  1512. }
        ^
  1513. 
  1514. const AVPixFmtDescriptor *av_pix_fmt_desc_next(const AVPixFmtDescriptor *prev)

libavcodec/hevc.c:2768:23: 
2766. {
2767.     const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(frame->format);
2768.     int pixel_shift = desc->comp[0].depth_minus1 > 7;
                            ^
2769.     int i, j;
2770. 
