libavfilter/vf_pad.c:152: error: Null Dereference
  pointer `pix_desc` last assigned on line 146 could be null and is dereferenced at line 152, column 17.

libavfilter/vf_pad.c:142:1: start of procedure config_input()
140. }
141. 
142. static int config_input(AVFilterLink *inlink)
     ^
143. {
144.     AVFilterContext *ctx = inlink->dst;

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

libavfilter/vf_pad.c:145:5: 
143. {
144.     AVFilterContext *ctx = inlink->dst;
145.     PadContext *pad = ctx->priv;
         ^
146.     const AVPixFmtDescriptor *pix_desc = av_pix_fmt_desc_get(inlink->format);
147.     uint8_t rgba_color[4];

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

libavutil/pixdesc.c:1434:1: start of procedure av_pix_fmt_desc_get()
  1432. }
  1433. 
  1434. const AVPixFmtDescriptor *av_pix_fmt_desc_get(enum AVPixelFormat pix_fmt)
        ^
  1435. {
  1436.     if (pix_fmt < 0 || pix_fmt >= AV_PIX_FMT_NB)

libavutil/pixdesc.c:1436:9: Taking false branch
  1434. const AVPixFmtDescriptor *av_pix_fmt_desc_get(enum AVPixelFormat pix_fmt)
  1435. {
  1436.     if (pix_fmt < 0 || pix_fmt >= AV_PIX_FMT_NB)
                ^
  1437.         return NULL;
  1438.     return &av_pix_fmt_descriptors[pix_fmt];

libavutil/pixdesc.c:1436:24: Taking true branch
  1434. const AVPixFmtDescriptor *av_pix_fmt_desc_get(enum AVPixelFormat pix_fmt)
  1435. {
  1436.     if (pix_fmt < 0 || pix_fmt >= AV_PIX_FMT_NB)
                               ^
  1437.         return NULL;
  1438.     return &av_pix_fmt_descriptors[pix_fmt];

libavutil/pixdesc.c:1437:9: 
  1435. {
  1436.     if (pix_fmt < 0 || pix_fmt >= AV_PIX_FMT_NB)
  1437.         return NULL;
                ^
  1438.     return &av_pix_fmt_descriptors[pix_fmt];
  1439. }

libavutil/pixdesc.c:1439:1: return from a call to av_pix_fmt_desc_get
  1437.         return NULL;
  1438.     return &av_pix_fmt_descriptors[pix_fmt];
  1439. }
        ^
  1440. 
  1441. const AVPixFmtDescriptor *av_pix_fmt_desc_next(const AVPixFmtDescriptor *prev)

libavfilter/vf_pad.c:152:5: 
150.     char *expr;
151. 
152.     pad->hsub = pix_desc->log2_chroma_w;
         ^
153.     pad->vsub = pix_desc->log2_chroma_h;
154. 
