libavfilter/vf_crop.c:180: error: Null Dereference
  pointer `pix_desc` last assigned on line 161 could be null and is dereferenced at line 180, column 18.

libavfilter/vf_crop.c:157:1: start of procedure config_input()
155. }
156. 
157. static int config_input(AVFilterLink *link)
     ^
158. {
159.     AVFilterContext *ctx = link->dst;

libavfilter/vf_crop.c:159:5: 
157. static int config_input(AVFilterLink *link)
158. {
159.     AVFilterContext *ctx = link->dst;
         ^
160.     CropContext *crop = ctx->priv;
161.     const AVPixFmtDescriptor *pix_desc = av_pix_fmt_desc_get(link->format);

libavfilter/vf_crop.c:160:5: 
158. {
159.     AVFilterContext *ctx = link->dst;
160.     CropContext *crop = ctx->priv;
         ^
161.     const AVPixFmtDescriptor *pix_desc = av_pix_fmt_desc_get(link->format);
162.     int ret;

libavfilter/vf_crop.c:161:5: 
159.     AVFilterContext *ctx = link->dst;
160.     CropContext *crop = ctx->priv;
161.     const AVPixFmtDescriptor *pix_desc = av_pix_fmt_desc_get(link->format);
         ^
162.     int ret;
163.     const char *expr;

libavutil/pixdesc.c:1199:1: start of procedure av_pix_fmt_desc_get()
  1197. }
  1198. 
  1199. const AVPixFmtDescriptor *av_pix_fmt_desc_get(enum AVPixelFormat pix_fmt)
        ^
  1200. {
  1201.     if (pix_fmt < 0 || pix_fmt >= AV_PIX_FMT_NB)

libavutil/pixdesc.c:1201:9: Taking false branch
  1199. const AVPixFmtDescriptor *av_pix_fmt_desc_get(enum AVPixelFormat pix_fmt)
  1200. {
  1201.     if (pix_fmt < 0 || pix_fmt >= AV_PIX_FMT_NB)
                ^
  1202.         return NULL;
  1203.     return &av_pix_fmt_descriptors[pix_fmt];

libavutil/pixdesc.c:1201:24: Taking true branch
  1199. const AVPixFmtDescriptor *av_pix_fmt_desc_get(enum AVPixelFormat pix_fmt)
  1200. {
  1201.     if (pix_fmt < 0 || pix_fmt >= AV_PIX_FMT_NB)
                               ^
  1202.         return NULL;
  1203.     return &av_pix_fmt_descriptors[pix_fmt];

libavutil/pixdesc.c:1202:9: 
  1200. {
  1201.     if (pix_fmt < 0 || pix_fmt >= AV_PIX_FMT_NB)
  1202.         return NULL;
                ^
  1203.     return &av_pix_fmt_descriptors[pix_fmt];
  1204. }

libavutil/pixdesc.c:1204:1: return from a call to av_pix_fmt_desc_get
  1202.         return NULL;
  1203.     return &av_pix_fmt_descriptors[pix_fmt];
  1204. }
        ^
  1205. 
  1206. const AVPixFmtDescriptor *av_pix_fmt_desc_next(const AVPixFmtDescriptor *prev)

libavfilter/vf_crop.c:166:5: 
164.     double res;
165. 
166.     crop->var_values[VAR_E]     = M_E;
         ^
167.     crop->var_values[VAR_PHI]   = M_PHI;
168.     crop->var_values[VAR_PI]    = M_PI;

libavfilter/vf_crop.c:167:5: 
165. 
166.     crop->var_values[VAR_E]     = M_E;
167.     crop->var_values[VAR_PHI]   = M_PHI;
         ^
168.     crop->var_values[VAR_PI]    = M_PI;
169.     crop->var_values[VAR_IN_W]  = crop->var_values[VAR_IW] = ctx->inputs[0]->w;

libavfilter/vf_crop.c:168:5: 
166.     crop->var_values[VAR_E]     = M_E;
167.     crop->var_values[VAR_PHI]   = M_PHI;
168.     crop->var_values[VAR_PI]    = M_PI;
         ^
169.     crop->var_values[VAR_IN_W]  = crop->var_values[VAR_IW] = ctx->inputs[0]->w;
170.     crop->var_values[VAR_IN_H]  = crop->var_values[VAR_IH] = ctx->inputs[0]->h;

libavfilter/vf_crop.c:169:5: 
167.     crop->var_values[VAR_PHI]   = M_PHI;
168.     crop->var_values[VAR_PI]    = M_PI;
169.     crop->var_values[VAR_IN_W]  = crop->var_values[VAR_IW] = ctx->inputs[0]->w;
         ^
170.     crop->var_values[VAR_IN_H]  = crop->var_values[VAR_IH] = ctx->inputs[0]->h;
171.     crop->var_values[VAR_X]     = NAN;

libavfilter/vf_crop.c:170:5: 
168.     crop->var_values[VAR_PI]    = M_PI;
169.     crop->var_values[VAR_IN_W]  = crop->var_values[VAR_IW] = ctx->inputs[0]->w;
170.     crop->var_values[VAR_IN_H]  = crop->var_values[VAR_IH] = ctx->inputs[0]->h;
         ^
171.     crop->var_values[VAR_X]     = NAN;
172.     crop->var_values[VAR_Y]     = NAN;

libavfilter/vf_crop.c:171:5: Skipping __builtin_nanf(): method has no implementation
169.     crop->var_values[VAR_IN_W]  = crop->var_values[VAR_IW] = ctx->inputs[0]->w;
170.     crop->var_values[VAR_IN_H]  = crop->var_values[VAR_IH] = ctx->inputs[0]->h;
171.     crop->var_values[VAR_X]     = NAN;
         ^
172.     crop->var_values[VAR_Y]     = NAN;
173.     crop->var_values[VAR_OUT_W] = crop->var_values[VAR_OW] = NAN;

libavfilter/vf_crop.c:172:5: Skipping __builtin_nanf(): method has no implementation
170.     crop->var_values[VAR_IN_H]  = crop->var_values[VAR_IH] = ctx->inputs[0]->h;
171.     crop->var_values[VAR_X]     = NAN;
172.     crop->var_values[VAR_Y]     = NAN;
         ^
173.     crop->var_values[VAR_OUT_W] = crop->var_values[VAR_OW] = NAN;
174.     crop->var_values[VAR_OUT_H] = crop->var_values[VAR_OH] = NAN;

libavfilter/vf_crop.c:173:5: Skipping __builtin_nanf(): method has no implementation
171.     crop->var_values[VAR_X]     = NAN;
172.     crop->var_values[VAR_Y]     = NAN;
173.     crop->var_values[VAR_OUT_W] = crop->var_values[VAR_OW] = NAN;
         ^
174.     crop->var_values[VAR_OUT_H] = crop->var_values[VAR_OH] = NAN;
175.     crop->var_values[VAR_N]     = 0;

libavfilter/vf_crop.c:174:5: Skipping __builtin_nanf(): method has no implementation
172.     crop->var_values[VAR_Y]     = NAN;
173.     crop->var_values[VAR_OUT_W] = crop->var_values[VAR_OW] = NAN;
174.     crop->var_values[VAR_OUT_H] = crop->var_values[VAR_OH] = NAN;
         ^
175.     crop->var_values[VAR_N]     = 0;
176.     crop->var_values[VAR_T]     = NAN;

libavfilter/vf_crop.c:175:5: 
173.     crop->var_values[VAR_OUT_W] = crop->var_values[VAR_OW] = NAN;
174.     crop->var_values[VAR_OUT_H] = crop->var_values[VAR_OH] = NAN;
175.     crop->var_values[VAR_N]     = 0;
         ^
176.     crop->var_values[VAR_T]     = NAN;
177.     crop->var_values[VAR_POS]   = NAN;

libavfilter/vf_crop.c:176:5: Skipping __builtin_nanf(): method has no implementation
174.     crop->var_values[VAR_OUT_H] = crop->var_values[VAR_OH] = NAN;
175.     crop->var_values[VAR_N]     = 0;
176.     crop->var_values[VAR_T]     = NAN;
         ^
177.     crop->var_values[VAR_POS]   = NAN;
178. 

libavfilter/vf_crop.c:177:5: Skipping __builtin_nanf(): method has no implementation
175.     crop->var_values[VAR_N]     = 0;
176.     crop->var_values[VAR_T]     = NAN;
177.     crop->var_values[VAR_POS]   = NAN;
         ^
178. 
179.     av_image_fill_max_pixsteps(crop->max_step, NULL, pix_desc);

libavfilter/vf_crop.c:179:5: Skipping av_image_fill_max_pixsteps(): empty list of specs
177.     crop->var_values[VAR_POS]   = NAN;
178. 
179.     av_image_fill_max_pixsteps(crop->max_step, NULL, pix_desc);
         ^
180.     crop->hsub = pix_desc->log2_chroma_w;
181.     crop->vsub = pix_desc->log2_chroma_h;

libavfilter/vf_crop.c:180:5: 
178. 
179.     av_image_fill_max_pixsteps(crop->max_step, NULL, pix_desc);
180.     crop->hsub = pix_desc->log2_chroma_w;
         ^
181.     crop->vsub = pix_desc->log2_chroma_h;
182. 
