libavfilter/vf_lut.c:204: error: Null Dereference
  pointer `desc` last assigned on line 200 could be null and is dereferenced at line 204, column 17.

libavfilter/vf_lut.c:196:1: start of procedure config_props()
194. };
195. 
196. static int config_props(AVFilterLink *inlink)
     ^
197. {
198.     AVFilterContext *ctx = inlink->dst;

libavfilter/vf_lut.c:198:5: 
196. static int config_props(AVFilterLink *inlink)
197. {
198.     AVFilterContext *ctx = inlink->dst;
         ^
199.     LutContext *lut = ctx->priv;
200.     const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(inlink->format);

libavfilter/vf_lut.c:199:5: 
197. {
198.     AVFilterContext *ctx = inlink->dst;
199.     LutContext *lut = ctx->priv;
         ^
200.     const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(inlink->format);
201.     int min[4], max[4];

libavfilter/vf_lut.c:200:5: 
198.     AVFilterContext *ctx = inlink->dst;
199.     LutContext *lut = ctx->priv;
200.     const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(inlink->format);
         ^
201.     int min[4], max[4];
202.     int val, comp, ret;

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_lut.c:204:5: 
202.     int val, comp, ret;
203. 
204.     lut->hsub = desc->log2_chroma_w;
         ^
205.     lut->vsub = desc->log2_chroma_h;
206. 
