libavfilter/vf_unsharp.c:181: error: Null Dereference
  pointer `desc` last assigned on line 179 could be null and is dereferenced at line 181, column 21.

libavfilter/vf_unsharp.c:176:1: start of procedure config_props()
174. }
175. 
176. static int config_props(AVFilterLink *link)
     ^
177. {
178.     UnsharpContext *unsharp = link->dst->priv;

libavfilter/vf_unsharp.c:178:5: 
176. static int config_props(AVFilterLink *link)
177. {
178.     UnsharpContext *unsharp = link->dst->priv;
         ^
179.     const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(link->format);
180. 

libavfilter/vf_unsharp.c:179:5: 
177. {
178.     UnsharpContext *unsharp = link->dst->priv;
179.     const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(link->format);
         ^
180. 
181.     unsharp->hsub = desc->log2_chroma_w;

libavutil/pixdesc.c:1464:1: start of procedure av_pix_fmt_desc_get()
  1462. }
  1463. 
  1464. const AVPixFmtDescriptor *av_pix_fmt_desc_get(enum AVPixelFormat pix_fmt)
        ^
  1465. {
  1466.     if (pix_fmt < 0 || pix_fmt >= AV_PIX_FMT_NB)

libavutil/pixdesc.c:1466:9: Taking false branch
  1464. const AVPixFmtDescriptor *av_pix_fmt_desc_get(enum AVPixelFormat pix_fmt)
  1465. {
  1466.     if (pix_fmt < 0 || pix_fmt >= AV_PIX_FMT_NB)
                ^
  1467.         return NULL;
  1468.     return &av_pix_fmt_descriptors[pix_fmt];

libavutil/pixdesc.c:1466:24: Taking true branch
  1464. const AVPixFmtDescriptor *av_pix_fmt_desc_get(enum AVPixelFormat pix_fmt)
  1465. {
  1466.     if (pix_fmt < 0 || pix_fmt >= AV_PIX_FMT_NB)
                               ^
  1467.         return NULL;
  1468.     return &av_pix_fmt_descriptors[pix_fmt];

libavutil/pixdesc.c:1467:9: 
  1465. {
  1466.     if (pix_fmt < 0 || pix_fmt >= AV_PIX_FMT_NB)
  1467.         return NULL;
                ^
  1468.     return &av_pix_fmt_descriptors[pix_fmt];
  1469. }

libavutil/pixdesc.c:1469:1: return from a call to av_pix_fmt_desc_get
  1467.         return NULL;
  1468.     return &av_pix_fmt_descriptors[pix_fmt];
  1469. }
        ^
  1470. 
  1471. const AVPixFmtDescriptor *av_pix_fmt_desc_next(const AVPixFmtDescriptor *prev)

libavfilter/vf_unsharp.c:181:5: 
179.     const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(link->format);
180. 
181.     unsharp->hsub = desc->log2_chroma_w;
         ^
182.     unsharp->vsub = desc->log2_chroma_h;
183. 

static int config_props(AVFilterLink *link)
{
    UnsharpContext *unsharp = link->dst->priv;
    const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(link->format);
    unsharp->hsub = desc->log2_chroma_w;
    unsharp->vsub = desc->log2_chroma_h;
    init_filter_param(link->dst, &unsharp->luma,   "luma",   link->w);
    init_filter_param(link->dst, &unsharp->chroma, "chroma", SHIFTUP(link->w, unsharp->hsub));
    return 0;
}
['static int config_props(AVFilterLink *link)\n{\n    UnsharpContext *unsharp = link->dst->priv;\n    const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(link->format);\n    unsharp->hsub = desc->log2_chroma_w;\n    unsharp->vsub = desc->log2_chroma_h;\n    init_filter_param(link->dst, &unsharp->luma,   "luma",   link->w);\n    init_filter_param(link->dst, &unsharp->chroma, "chroma", SHIFTUP(link->w, unsharp->hsub));\n    return 0;\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}']