libavfilter/vf_pad.c:153: error: Null Dereference
  pointer `pix_desc` last assigned on line 147 could be null and is dereferenced at line 153, column 17.

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

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

libavfilter/vf_pad.c:146:5: 
144. {
145.     AVFilterContext *ctx = inlink->dst;
146.     PadContext *pad = ctx->priv;
         ^
147.     const AVPixFmtDescriptor *pix_desc = av_pix_fmt_desc_get(inlink->format);
148.     uint8_t rgba_color[4];

libavfilter/vf_pad.c:147:5: 
145.     AVFilterContext *ctx = inlink->dst;
146.     PadContext *pad = ctx->priv;
147.     const AVPixFmtDescriptor *pix_desc = av_pix_fmt_desc_get(inlink->format);
         ^
148.     uint8_t rgba_color[4];
149.     int ret, is_packed_rgba;

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_pad.c:153:5: 
151.     char *expr;
152. 
153.     pad->hsub = pix_desc->log2_chroma_w;
         ^
154.     pad->vsub = pix_desc->log2_chroma_h;
155. 
