libavcodec/mpegvideo_enc.c:1369: error: Null Dereference
  pointer `desc` last assigned on line 1368 could be null and is dereferenced at line 1369, column 22.

libavcodec/mpegvideo_enc.c:1361:1: start of procedure frame_end()
1359. }
1360. 
1361. static void frame_end(MpegEncContext *s)
      ^
1362. {
1363.     int i;

libavcodec/mpegvideo_enc.c:1365:9: Taking true branch
1363.     int i;
1364. 
1365.     if (s->unrestricted_mv &&
              ^
1366.         s->current_picture.reference &&
1367.         !s->intra_only) {

libavcodec/mpegvideo_enc.c:1366:9: Taking true branch
1364. 
1365.     if (s->unrestricted_mv &&
1366.         s->current_picture.reference &&
              ^
1367.         !s->intra_only) {
1368.         const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(s->avctx->pix_fmt);

libavcodec/mpegvideo_enc.c:1367:10: Taking true branch
1365.     if (s->unrestricted_mv &&
1366.         s->current_picture.reference &&
1367.         !s->intra_only) {
               ^
1368.         const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(s->avctx->pix_fmt);
1369.         int hshift = desc->log2_chroma_w;

libavcodec/mpegvideo_enc.c:1368:9: 
1366.         s->current_picture.reference &&
1367.         !s->intra_only) {
1368.         const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(s->avctx->pix_fmt);
              ^
1369.         int hshift = desc->log2_chroma_w;
1370.         int vshift = desc->log2_chroma_h;

libavutil/pixdesc.c:1570:1: start of procedure av_pix_fmt_desc_get()
  1568. }
  1569. 
  1570. const AVPixFmtDescriptor *av_pix_fmt_desc_get(enum AVPixelFormat pix_fmt)
        ^
  1571. {
  1572.     if (pix_fmt < 0 || pix_fmt >= AV_PIX_FMT_NB)

libavutil/pixdesc.c:1572:9: Taking false branch
  1570. const AVPixFmtDescriptor *av_pix_fmt_desc_get(enum AVPixelFormat pix_fmt)
  1571. {
  1572.     if (pix_fmt < 0 || pix_fmt >= AV_PIX_FMT_NB)
                ^
  1573.         return NULL;
  1574.     return &av_pix_fmt_descriptors[pix_fmt];

libavutil/pixdesc.c:1572:24: Taking true branch
  1570. const AVPixFmtDescriptor *av_pix_fmt_desc_get(enum AVPixelFormat pix_fmt)
  1571. {
  1572.     if (pix_fmt < 0 || pix_fmt >= AV_PIX_FMT_NB)
                               ^
  1573.         return NULL;
  1574.     return &av_pix_fmt_descriptors[pix_fmt];

libavutil/pixdesc.c:1573:9: 
  1571. {
  1572.     if (pix_fmt < 0 || pix_fmt >= AV_PIX_FMT_NB)
  1573.         return NULL;
                ^
  1574.     return &av_pix_fmt_descriptors[pix_fmt];
  1575. }

libavutil/pixdesc.c:1575:1: return from a call to av_pix_fmt_desc_get
  1573.         return NULL;
  1574.     return &av_pix_fmt_descriptors[pix_fmt];
  1575. }
        ^
  1576. 
  1577. const AVPixFmtDescriptor *av_pix_fmt_desc_next(const AVPixFmtDescriptor *prev)

libavcodec/mpegvideo_enc.c:1369:9: 
1367.         !s->intra_only) {
1368.         const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(s->avctx->pix_fmt);
1369.         int hshift = desc->log2_chroma_w;
              ^
1370.         int vshift = desc->log2_chroma_h;
1371.         s->dsp.draw_edges(s->current_picture.f->data[0], s->linesize,
