libavcodec/imgconvert.c:71: error: Null Dereference
  pointer `dst_desc` last assigned on line 70 could be null and is dereferenced at line 71, column 34.

libavcodec/imgconvert.c:65:1: start of procedure avcodec_get_pix_fmt_loss()
63. }
64. 
65. int avcodec_get_pix_fmt_loss(enum AVPixelFormat dst_pix_fmt,
    ^
66.                              enum AVPixelFormat src_pix_fmt,
67.                              int has_alpha)

libavcodec/imgconvert.c:69:5: 
67.                              int has_alpha)
68. {
69.     const AVPixFmtDescriptor *src_desc = av_pix_fmt_desc_get(src_pix_fmt);
        ^
70.     const AVPixFmtDescriptor *dst_desc = av_pix_fmt_desc_get(dst_pix_fmt);
71.     int loss, i, nb_components = FFMIN(src_desc->nb_components,

libavutil/pixdesc.c:1434:1: start of procedure av_pix_fmt_desc_get()
  1432. }
  1433. 
  1434. const AVPixFmtDescriptor *av_pix_fmt_desc_get(enum AVPixelFormat pix_fmt)
        ^
  1435. {
  1436.     if (pix_fmt < 0 || pix_fmt >= AV_PIX_FMT_NB)

libavutil/pixdesc.c:1436:9: Taking false branch
  1434. const AVPixFmtDescriptor *av_pix_fmt_desc_get(enum AVPixelFormat pix_fmt)
  1435. {
  1436.     if (pix_fmt < 0 || pix_fmt >= AV_PIX_FMT_NB)
                ^
  1437.         return NULL;
  1438.     return &av_pix_fmt_descriptors[pix_fmt];

libavutil/pixdesc.c:1436:24: Taking false branch
  1434. const AVPixFmtDescriptor *av_pix_fmt_desc_get(enum AVPixelFormat pix_fmt)
  1435. {
  1436.     if (pix_fmt < 0 || pix_fmt >= AV_PIX_FMT_NB)
                               ^
  1437.         return NULL;
  1438.     return &av_pix_fmt_descriptors[pix_fmt];

libavutil/pixdesc.c:1438:5: 
  1436.     if (pix_fmt < 0 || pix_fmt >= AV_PIX_FMT_NB)
  1437.         return NULL;
  1438.     return &av_pix_fmt_descriptors[pix_fmt];
            ^
  1439. }
  1440. 

libavutil/pixdesc.c:1439:1: return from a call to av_pix_fmt_desc_get
  1437.         return NULL;
  1438.     return &av_pix_fmt_descriptors[pix_fmt];
  1439. }
        ^
  1440. 
  1441. const AVPixFmtDescriptor *av_pix_fmt_desc_next(const AVPixFmtDescriptor *prev)

libavcodec/imgconvert.c:70:5: 
68. {
69.     const AVPixFmtDescriptor *src_desc = av_pix_fmt_desc_get(src_pix_fmt);
70.     const AVPixFmtDescriptor *dst_desc = av_pix_fmt_desc_get(dst_pix_fmt);
        ^
71.     int loss, i, nb_components = FFMIN(src_desc->nb_components,
72.                                        dst_desc->nb_components);

libavutil/pixdesc.c:1434:1: start of procedure av_pix_fmt_desc_get()
  1432. }
  1433. 
  1434. const AVPixFmtDescriptor *av_pix_fmt_desc_get(enum AVPixelFormat pix_fmt)
        ^
  1435. {
  1436.     if (pix_fmt < 0 || pix_fmt >= AV_PIX_FMT_NB)

libavutil/pixdesc.c:1436:9: Taking false branch
  1434. const AVPixFmtDescriptor *av_pix_fmt_desc_get(enum AVPixelFormat pix_fmt)
  1435. {
  1436.     if (pix_fmt < 0 || pix_fmt >= AV_PIX_FMT_NB)
                ^
  1437.         return NULL;
  1438.     return &av_pix_fmt_descriptors[pix_fmt];

libavutil/pixdesc.c:1436:24: Taking true branch
  1434. const AVPixFmtDescriptor *av_pix_fmt_desc_get(enum AVPixelFormat pix_fmt)
  1435. {
  1436.     if (pix_fmt < 0 || pix_fmt >= AV_PIX_FMT_NB)
                               ^
  1437.         return NULL;
  1438.     return &av_pix_fmt_descriptors[pix_fmt];

libavutil/pixdesc.c:1437:9: 
  1435. {
  1436.     if (pix_fmt < 0 || pix_fmt >= AV_PIX_FMT_NB)
  1437.         return NULL;
                ^
  1438.     return &av_pix_fmt_descriptors[pix_fmt];
  1439. }

libavutil/pixdesc.c:1439:1: return from a call to av_pix_fmt_desc_get
  1437.         return NULL;
  1438.     return &av_pix_fmt_descriptors[pix_fmt];
  1439. }
        ^
  1440. 
  1441. const AVPixFmtDescriptor *av_pix_fmt_desc_next(const AVPixFmtDescriptor *prev)

libavcodec/imgconvert.c:71:34: 
69.     const AVPixFmtDescriptor *src_desc = av_pix_fmt_desc_get(src_pix_fmt);
70.     const AVPixFmtDescriptor *dst_desc = av_pix_fmt_desc_get(dst_pix_fmt);
71.     int loss, i, nb_components = FFMIN(src_desc->nb_components,
                                     ^
72.                                        dst_desc->nb_components);
73. 
