libswscale/utils.c:788: error: Null Dereference
  pointer `desc` last assigned on line 787 could be null and is dereferenced at line 788, column 10.

libswscale/utils.c:785:1: start of procedure getSubSampleFactors()
783. #endif /* HAVE_MMXEXT_INLINE */
784. 
785. static void getSubSampleFactors(int *h, int *v, enum AVPixelFormat format)
     ^
786. {
787.     const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(format);

libswscale/utils.c:787:5: 
785. static void getSubSampleFactors(int *h, int *v, enum AVPixelFormat format)
786. {
787.     const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(format);
         ^
788.     *h = desc->log2_chroma_w;
789.     *v = desc->log2_chroma_h;

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)

libswscale/utils.c:788:5: 
786. {
787.     const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(format);
788.     *h = desc->log2_chroma_w;
         ^
789.     *v = desc->log2_chroma_h;
790. }

static void getSubSampleFactors(int *h, int *v, enum AVPixelFormat format)
{
    const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(format);
    *h = desc->log2_chroma_w;
    *v = desc->log2_chroma_h;
}
['static void getSubSampleFactors(int *h, int *v, enum AVPixelFormat format)\n{\n    const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(format);\n    *h = desc->log2_chroma_w;\n    *v = desc->log2_chroma_h;\n}', 'const AVPixFmtDescriptor *av_pix_fmt_desc_get(enum AVPixelFormat pix_fmt)\n{\n    if (pix_fmt < 0 || pix_fmt >= AV_PIX_FMT_NB)\n        return NULL;\n    return &av_pix_fmt_descriptors[pix_fmt];\n}']