libavcodec/h264.c:130: error: Null Dereference
  pointer `desc` last assigned on line 129 could be null and is dereferenced at line 130, column 18.

libavcodec/h264.c:124:1: start of procedure ff_h264_draw_horiz_band()
122. }
123. 
124. void ff_h264_draw_horiz_band(H264Context *h, int y, int height)
     ^
125. {
126.     AVCodecContext *avctx = h->avctx;

libavcodec/h264.c:126:5: 
124. void ff_h264_draw_horiz_band(H264Context *h, int y, int height)
125. {
126.     AVCodecContext *avctx = h->avctx;
         ^
127.     Picture *cur  = &h->cur_pic;
128.     Picture *last = h->ref_list[0][0].f.data[0] ? &h->ref_list[0][0] : NULL;

libavcodec/h264.c:127:5: 
125. {
126.     AVCodecContext *avctx = h->avctx;
127.     Picture *cur  = &h->cur_pic;
         ^
128.     Picture *last = h->ref_list[0][0].f.data[0] ? &h->ref_list[0][0] : NULL;
129.     const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(avctx->pix_fmt);

libavcodec/h264.c:128:21: Condition is true
126.     AVCodecContext *avctx = h->avctx;
127.     Picture *cur  = &h->cur_pic;
128.     Picture *last = h->ref_list[0][0].f.data[0] ? &h->ref_list[0][0] : NULL;
                         ^
129.     const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(avctx->pix_fmt);
130.     int vshift = desc->log2_chroma_h;

libavcodec/h264.c:128:5: 
126.     AVCodecContext *avctx = h->avctx;
127.     Picture *cur  = &h->cur_pic;
128.     Picture *last = h->ref_list[0][0].f.data[0] ? &h->ref_list[0][0] : NULL;
         ^
129.     const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(avctx->pix_fmt);
130.     int vshift = desc->log2_chroma_h;

libavcodec/h264.c:129:5: 
127.     Picture *cur  = &h->cur_pic;
128.     Picture *last = h->ref_list[0][0].f.data[0] ? &h->ref_list[0][0] : NULL;
129.     const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(avctx->pix_fmt);
         ^
130.     int vshift = desc->log2_chroma_h;
131.     const int field_pic = h->picture_structure != PICT_FRAME;

libavutil/pixdesc.c:1468:1: start of procedure av_pix_fmt_desc_get()
  1466. }
  1467. 
  1468. const AVPixFmtDescriptor *av_pix_fmt_desc_get(enum AVPixelFormat pix_fmt)
        ^
  1469. {
  1470.     if (pix_fmt < 0 || pix_fmt >= AV_PIX_FMT_NB)

libavutil/pixdesc.c:1470:9: Taking false branch
  1468. const AVPixFmtDescriptor *av_pix_fmt_desc_get(enum AVPixelFormat pix_fmt)
  1469. {
  1470.     if (pix_fmt < 0 || pix_fmt >= AV_PIX_FMT_NB)
                ^
  1471.         return NULL;
  1472.     return &av_pix_fmt_descriptors[pix_fmt];

libavutil/pixdesc.c:1470:24: Taking true branch
  1468. const AVPixFmtDescriptor *av_pix_fmt_desc_get(enum AVPixelFormat pix_fmt)
  1469. {
  1470.     if (pix_fmt < 0 || pix_fmt >= AV_PIX_FMT_NB)
                               ^
  1471.         return NULL;
  1472.     return &av_pix_fmt_descriptors[pix_fmt];

libavutil/pixdesc.c:1471:9: 
  1469. {
  1470.     if (pix_fmt < 0 || pix_fmt >= AV_PIX_FMT_NB)
  1471.         return NULL;
                ^
  1472.     return &av_pix_fmt_descriptors[pix_fmt];
  1473. }

libavutil/pixdesc.c:1473:1: return from a call to av_pix_fmt_desc_get
  1471.         return NULL;
  1472.     return &av_pix_fmt_descriptors[pix_fmt];
  1473. }
        ^
  1474. 
  1475. const AVPixFmtDescriptor *av_pix_fmt_desc_next(const AVPixFmtDescriptor *prev)

libavcodec/h264.c:130:5: 
128.     Picture *last = h->ref_list[0][0].f.data[0] ? &h->ref_list[0][0] : NULL;
129.     const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(avctx->pix_fmt);
130.     int vshift = desc->log2_chroma_h;
         ^
131.     const int field_pic = h->picture_structure != PICT_FRAME;
132.     if (field_pic) {
