libavcodec/mpegvideo_enc.c:1394: error: Null Dereference
  pointer `desc` last assigned on line 1393 could be null and is dereferenced at line 1394, column 22.

libavcodec/mpegvideo_enc.c:1386:1: start of procedure frame_end()
1384. }
1385. 
1386. static void frame_end(MpegEncContext *s)
      ^
1387. {
1388.     int i;

libavcodec/mpegvideo_enc.c:1390:9: Taking true branch
1388.     int i;
1389. 
1390.     if (s->unrestricted_mv &&
              ^
1391.         s->current_picture.reference &&
1392.         !s->intra_only) {

libavcodec/mpegvideo_enc.c:1391:9: Taking true branch
1389. 
1390.     if (s->unrestricted_mv &&
1391.         s->current_picture.reference &&
              ^
1392.         !s->intra_only) {
1393.         const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(s->avctx->pix_fmt);

libavcodec/mpegvideo_enc.c:1392:10: Taking true branch
1390.     if (s->unrestricted_mv &&
1391.         s->current_picture.reference &&
1392.         !s->intra_only) {
               ^
1393.         const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(s->avctx->pix_fmt);
1394.         int hshift = desc->log2_chroma_w;

libavcodec/mpegvideo_enc.c:1393:9: 
1391.         s->current_picture.reference &&
1392.         !s->intra_only) {
1393.         const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(s->avctx->pix_fmt);
              ^
1394.         int hshift = desc->log2_chroma_w;
1395.         int vshift = desc->log2_chroma_h;

libavutil/pixdesc.c:1574:1: start of procedure av_pix_fmt_desc_get()
  1572. }
  1573. 
  1574. const AVPixFmtDescriptor *av_pix_fmt_desc_get(enum AVPixelFormat pix_fmt)
        ^
  1575. {
  1576.     if (pix_fmt < 0 || pix_fmt >= AV_PIX_FMT_NB)

libavutil/pixdesc.c:1576:9: Taking false branch
  1574. const AVPixFmtDescriptor *av_pix_fmt_desc_get(enum AVPixelFormat pix_fmt)
  1575. {
  1576.     if (pix_fmt < 0 || pix_fmt >= AV_PIX_FMT_NB)
                ^
  1577.         return NULL;
  1578.     return &av_pix_fmt_descriptors[pix_fmt];

libavutil/pixdesc.c:1576:24: Taking true branch
  1574. const AVPixFmtDescriptor *av_pix_fmt_desc_get(enum AVPixelFormat pix_fmt)
  1575. {
  1576.     if (pix_fmt < 0 || pix_fmt >= AV_PIX_FMT_NB)
                               ^
  1577.         return NULL;
  1578.     return &av_pix_fmt_descriptors[pix_fmt];

libavutil/pixdesc.c:1577:9: 
  1575. {
  1576.     if (pix_fmt < 0 || pix_fmt >= AV_PIX_FMT_NB)
  1577.         return NULL;
                ^
  1578.     return &av_pix_fmt_descriptors[pix_fmt];
  1579. }

libavutil/pixdesc.c:1579:1: return from a call to av_pix_fmt_desc_get
  1577.         return NULL;
  1578.     return &av_pix_fmt_descriptors[pix_fmt];
  1579. }
        ^
  1580. 
  1581. const AVPixFmtDescriptor *av_pix_fmt_desc_next(const AVPixFmtDescriptor *prev)

libavcodec/mpegvideo_enc.c:1394:9: 
1392.         !s->intra_only) {
1393.         const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(s->avctx->pix_fmt);
1394.         int hshift = desc->log2_chroma_w;
              ^
1395.         int vshift = desc->log2_chroma_h;
1396.         s->mpvencdsp.draw_edges(s->current_picture.f->data[0], s->linesize,
