libswscale/output.c:1281: error: Null Dereference
  pointer `desc` last assigned on line 1279 could be null and is dereferenced at line 1281, column 21.

libswscale/output.c:1271:1: start of procedure yuv2gbrp_full_X_c()
1269. YUV2RGBWRAPPERX(yuv2, rgb_full, rgb24_full,  AV_PIX_FMT_RGB24, 0)
1270. 
1271. static void
      ^
1272. yuv2gbrp_full_X_c(SwsContext *c, const int16_t *lumFilter,
1273.                   const int16_t **lumSrc, int lumFilterSize,

libswscale/output.c:1279:5: 
1277.                   int dstW, int y)
1278. {
1279.     const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(c->dstFormat);
          ^
1280.     int i;
1281.     int hasAlpha = (desc->flags & AV_PIX_FMT_FLAG_ALPHA) && alpSrc;

libavutil/pixdesc.c:1840:1: start of procedure av_pix_fmt_desc_get()
  1838. }
  1839. 
  1840. const AVPixFmtDescriptor *av_pix_fmt_desc_get(enum AVPixelFormat pix_fmt)
        ^
  1841. {
  1842.     if (pix_fmt < 0 || pix_fmt >= AV_PIX_FMT_NB)

libavutil/pixdesc.c:1842:9: Taking false branch
  1840. const AVPixFmtDescriptor *av_pix_fmt_desc_get(enum AVPixelFormat pix_fmt)
  1841. {
  1842.     if (pix_fmt < 0 || pix_fmt >= AV_PIX_FMT_NB)
                ^
  1843.         return NULL;
  1844.     return &av_pix_fmt_descriptors[pix_fmt];

libavutil/pixdesc.c:1842:24: Taking true branch
  1840. const AVPixFmtDescriptor *av_pix_fmt_desc_get(enum AVPixelFormat pix_fmt)
  1841. {
  1842.     if (pix_fmt < 0 || pix_fmt >= AV_PIX_FMT_NB)
                               ^
  1843.         return NULL;
  1844.     return &av_pix_fmt_descriptors[pix_fmt];

libavutil/pixdesc.c:1843:9: 
  1841. {
  1842.     if (pix_fmt < 0 || pix_fmt >= AV_PIX_FMT_NB)
  1843.         return NULL;
                ^
  1844.     return &av_pix_fmt_descriptors[pix_fmt];
  1845. }

libavutil/pixdesc.c:1845:1: return from a call to av_pix_fmt_desc_get
  1843.         return NULL;
  1844.     return &av_pix_fmt_descriptors[pix_fmt];
  1845. }
        ^
  1846. 
  1847. const AVPixFmtDescriptor *av_pix_fmt_desc_next(const AVPixFmtDescriptor *prev)

libswscale/output.c:1281:21: 
1279.     const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(c->dstFormat);
1280.     int i;
1281.     int hasAlpha = (desc->flags & AV_PIX_FMT_FLAG_ALPHA) && alpSrc;
                          ^
1282.     uint16_t **dest16 = (uint16_t**)dest;
1283.     int SH = 22 + 8 - desc->comp[0].depth;
