libavfilter/vf_crop.c:165: error: Null Dereference
  pointer `pix_desc` last assigned on line 147 could be null and is dereferenced at line 165, column 15.

libavfilter/vf_crop.c:143:1: start of procedure config_input()
141. }
142. 
143. static int config_input(AVFilterLink *link)
     ^
144. {
145.     AVFilterContext *ctx = link->dst;

libavfilter/vf_crop.c:145:5: 
143. static int config_input(AVFilterLink *link)
144. {
145.     AVFilterContext *ctx = link->dst;
         ^
146.     CropContext *s = ctx->priv;
147.     const AVPixFmtDescriptor *pix_desc = av_pix_fmt_desc_get(link->format);

libavfilter/vf_crop.c:146:5: 
144. {
145.     AVFilterContext *ctx = link->dst;
146.     CropContext *s = ctx->priv;
         ^
147.     const AVPixFmtDescriptor *pix_desc = av_pix_fmt_desc_get(link->format);
148.     int ret;

libavfilter/vf_crop.c:147:5: 
145.     AVFilterContext *ctx = link->dst;
146.     CropContext *s = ctx->priv;
147.     const AVPixFmtDescriptor *pix_desc = av_pix_fmt_desc_get(link->format);
         ^
148.     int ret;
149.     const char *expr;

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_crop.c:152:5: 
150.     double res;
151. 
152.     s->var_values[VAR_E]     = M_E;
         ^
153.     s->var_values[VAR_PHI]   = M_PHI;
154.     s->var_values[VAR_PI]    = M_PI;

libavfilter/vf_crop.c:153:5: 
151. 
152.     s->var_values[VAR_E]     = M_E;
153.     s->var_values[VAR_PHI]   = M_PHI;
         ^
154.     s->var_values[VAR_PI]    = M_PI;
155.     s->var_values[VAR_IN_W]  = s->var_values[VAR_IW] = ctx->inputs[0]->w;

libavfilter/vf_crop.c:154:5: 
152.     s->var_values[VAR_E]     = M_E;
153.     s->var_values[VAR_PHI]   = M_PHI;
154.     s->var_values[VAR_PI]    = M_PI;
         ^
155.     s->var_values[VAR_IN_W]  = s->var_values[VAR_IW] = ctx->inputs[0]->w;
156.     s->var_values[VAR_IN_H]  = s->var_values[VAR_IH] = ctx->inputs[0]->h;

libavfilter/vf_crop.c:155:5: 
153.     s->var_values[VAR_PHI]   = M_PHI;
154.     s->var_values[VAR_PI]    = M_PI;
155.     s->var_values[VAR_IN_W]  = s->var_values[VAR_IW] = ctx->inputs[0]->w;
         ^
156.     s->var_values[VAR_IN_H]  = s->var_values[VAR_IH] = ctx->inputs[0]->h;
157.     s->var_values[VAR_X]     = NAN;

libavfilter/vf_crop.c:156:5: 
154.     s->var_values[VAR_PI]    = M_PI;
155.     s->var_values[VAR_IN_W]  = s->var_values[VAR_IW] = ctx->inputs[0]->w;
156.     s->var_values[VAR_IN_H]  = s->var_values[VAR_IH] = ctx->inputs[0]->h;
         ^
157.     s->var_values[VAR_X]     = NAN;
158.     s->var_values[VAR_Y]     = NAN;

libavfilter/vf_crop.c:157:5: Skipping __builtin_nanf(): method has no implementation
155.     s->var_values[VAR_IN_W]  = s->var_values[VAR_IW] = ctx->inputs[0]->w;
156.     s->var_values[VAR_IN_H]  = s->var_values[VAR_IH] = ctx->inputs[0]->h;
157.     s->var_values[VAR_X]     = NAN;
         ^
158.     s->var_values[VAR_Y]     = NAN;
159.     s->var_values[VAR_OUT_W] = s->var_values[VAR_OW] = NAN;

libavfilter/vf_crop.c:158:5: Skipping __builtin_nanf(): method has no implementation
156.     s->var_values[VAR_IN_H]  = s->var_values[VAR_IH] = ctx->inputs[0]->h;
157.     s->var_values[VAR_X]     = NAN;
158.     s->var_values[VAR_Y]     = NAN;
         ^
159.     s->var_values[VAR_OUT_W] = s->var_values[VAR_OW] = NAN;
160.     s->var_values[VAR_OUT_H] = s->var_values[VAR_OH] = NAN;

libavfilter/vf_crop.c:159:5: Skipping __builtin_nanf(): method has no implementation
157.     s->var_values[VAR_X]     = NAN;
158.     s->var_values[VAR_Y]     = NAN;
159.     s->var_values[VAR_OUT_W] = s->var_values[VAR_OW] = NAN;
         ^
160.     s->var_values[VAR_OUT_H] = s->var_values[VAR_OH] = NAN;
161.     s->var_values[VAR_N]     = 0;

libavfilter/vf_crop.c:160:5: Skipping __builtin_nanf(): method has no implementation
158.     s->var_values[VAR_Y]     = NAN;
159.     s->var_values[VAR_OUT_W] = s->var_values[VAR_OW] = NAN;
160.     s->var_values[VAR_OUT_H] = s->var_values[VAR_OH] = NAN;
         ^
161.     s->var_values[VAR_N]     = 0;
162.     s->var_values[VAR_T]     = NAN;

libavfilter/vf_crop.c:161:5: 
159.     s->var_values[VAR_OUT_W] = s->var_values[VAR_OW] = NAN;
160.     s->var_values[VAR_OUT_H] = s->var_values[VAR_OH] = NAN;
161.     s->var_values[VAR_N]     = 0;
         ^
162.     s->var_values[VAR_T]     = NAN;
163. 

libavfilter/vf_crop.c:162:5: Skipping __builtin_nanf(): method has no implementation
160.     s->var_values[VAR_OUT_H] = s->var_values[VAR_OH] = NAN;
161.     s->var_values[VAR_N]     = 0;
162.     s->var_values[VAR_T]     = NAN;
         ^
163. 
164.     av_image_fill_max_pixsteps(s->max_step, NULL, pix_desc);

libavfilter/vf_crop.c:164:5: Skipping av_image_fill_max_pixsteps(): empty list of specs
162.     s->var_values[VAR_T]     = NAN;
163. 
164.     av_image_fill_max_pixsteps(s->max_step, NULL, pix_desc);
         ^
165.     s->hsub = pix_desc->log2_chroma_w;
166.     s->vsub = pix_desc->log2_chroma_h;

libavfilter/vf_crop.c:165:5: 
163. 
164.     av_image_fill_max_pixsteps(s->max_step, NULL, pix_desc);
165.     s->hsub = pix_desc->log2_chroma_w;
         ^
166.     s->vsub = pix_desc->log2_chroma_h;
167. 
