libavfilter/vf_lut.c:203: error: Null Dereference
  pointer `desc` last assigned on line 199 could be null and is dereferenced at line 203, column 17.

libavfilter/vf_lut.c:195:1: start of procedure config_props()
193. };
194. 
195. static int config_props(AVFilterLink *inlink)
     ^
196. {
197.     AVFilterContext *ctx = inlink->dst;

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

libavfilter/vf_lut.c:198:5: 
196. {
197.     AVFilterContext *ctx = inlink->dst;
198.     LutContext *lut = ctx->priv;
         ^
199.     const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(inlink->format);
200.     int min[4], max[4];

libavfilter/vf_lut.c:199:5: 
197.     AVFilterContext *ctx = inlink->dst;
198.     LutContext *lut = ctx->priv;
199.     const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(inlink->format);
         ^
200.     int min[4], max[4];
201.     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:203:5: 
201.     int val, comp, ret;
202. 
203.     lut->hsub = desc->log2_chroma_w;
         ^
204.     lut->vsub = desc->log2_chroma_h;
205. 
