libavcodec/mpegvideo_enc.c:1354: error: Null Dereference
  pointer `desc` last assigned on line 1353 could be null and is dereferenced at line 1354, column 22.

libavcodec/mpegvideo_enc.c:1346:1: start of procedure frame_end()
1344. }
1345. 
1346. static void frame_end(MpegEncContext *s)
      ^
1347. {
1348.     int i;

libavcodec/mpegvideo_enc.c:1350:9: Taking true branch
1348.     int i;
1349. 
1350.     if (s->unrestricted_mv &&
              ^
1351.         s->current_picture.reference &&
1352.         !s->intra_only) {

libavcodec/mpegvideo_enc.c:1351:9: Taking true branch
1349. 
1350.     if (s->unrestricted_mv &&
1351.         s->current_picture.reference &&
              ^
1352.         !s->intra_only) {
1353.         const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(s->avctx->pix_fmt);

libavcodec/mpegvideo_enc.c:1352:10: Taking true branch
1350.     if (s->unrestricted_mv &&
1351.         s->current_picture.reference &&
1352.         !s->intra_only) {
               ^
1353.         const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(s->avctx->pix_fmt);
1354.         int hshift = desc->log2_chroma_w;

libavcodec/mpegvideo_enc.c:1353:9: 
1351.         s->current_picture.reference &&
1352.         !s->intra_only) {
1353.         const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(s->avctx->pix_fmt);
              ^
1354.         int hshift = desc->log2_chroma_w;
1355.         int vshift = desc->log2_chroma_h;

libavutil/pixdesc.c:1507:1: start of procedure av_pix_fmt_desc_get()
  1505. }
  1506. 
  1507. const AVPixFmtDescriptor *av_pix_fmt_desc_get(enum AVPixelFormat pix_fmt)
        ^
  1508. {
  1509.     if (pix_fmt < 0 || pix_fmt >= AV_PIX_FMT_NB)

libavutil/pixdesc.c:1509:9: Taking false branch
  1507. const AVPixFmtDescriptor *av_pix_fmt_desc_get(enum AVPixelFormat pix_fmt)
  1508. {
  1509.     if (pix_fmt < 0 || pix_fmt >= AV_PIX_FMT_NB)
                ^
  1510.         return NULL;
  1511.     return &av_pix_fmt_descriptors[pix_fmt];

libavutil/pixdesc.c:1509:24: Taking true branch
  1507. const AVPixFmtDescriptor *av_pix_fmt_desc_get(enum AVPixelFormat pix_fmt)
  1508. {
  1509.     if (pix_fmt < 0 || pix_fmt >= AV_PIX_FMT_NB)
                               ^
  1510.         return NULL;
  1511.     return &av_pix_fmt_descriptors[pix_fmt];

libavutil/pixdesc.c:1510:9: 
  1508. {
  1509.     if (pix_fmt < 0 || pix_fmt >= AV_PIX_FMT_NB)
  1510.         return NULL;
                ^
  1511.     return &av_pix_fmt_descriptors[pix_fmt];
  1512. }

libavutil/pixdesc.c:1512:1: return from a call to av_pix_fmt_desc_get
  1510.         return NULL;
  1511.     return &av_pix_fmt_descriptors[pix_fmt];
  1512. }
        ^
  1513. 
  1514. const AVPixFmtDescriptor *av_pix_fmt_desc_next(const AVPixFmtDescriptor *prev)

libavcodec/mpegvideo_enc.c:1354:9: 
1352.         !s->intra_only) {
1353.         const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(s->avctx->pix_fmt);
1354.         int hshift = desc->log2_chroma_w;
              ^
1355.         int vshift = desc->log2_chroma_h;
1356.         s->dsp.draw_edges(s->current_picture.f.data[0], s->linesize,

static void frame_end(MpegEncContext *s)
{
    int i;
    if (s->unrestricted_mv &&
        s->current_picture.reference &&
        !s->intra_only) {
        const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(s->avctx->pix_fmt);
        int hshift = desc->log2_chroma_w;
        int vshift = desc->log2_chroma_h;
        s->dsp.draw_edges(s->current_picture.f.data[0], s->linesize,
                          s->h_edge_pos, s->v_edge_pos,
                          EDGE_WIDTH, EDGE_WIDTH,
                          EDGE_TOP | EDGE_BOTTOM);
        s->dsp.draw_edges(s->current_picture.f.data[1], s->uvlinesize,
                          s->h_edge_pos >> hshift, s->v_edge_pos >> vshift,
                          EDGE_WIDTH >> hshift, EDGE_WIDTH >> vshift,
                          EDGE_TOP | EDGE_BOTTOM);
        s->dsp.draw_edges(s->current_picture.f.data[2], s->uvlinesize,
                          s->h_edge_pos >> hshift, s->v_edge_pos >> vshift,
                          EDGE_WIDTH >> hshift, EDGE_WIDTH >> vshift,
                          EDGE_TOP | EDGE_BOTTOM);
    }
    emms_c();
    s->last_pict_type                 = s->pict_type;
    s->last_lambda_for [s->pict_type] = s->current_picture_ptr->f.quality;
    if (s->pict_type!= AV_PICTURE_TYPE_B)
        s->last_non_b_pict_type = s->pict_type;
    if (s->encoding) {
        for (i = 0; i < MAX_PICTURE_COUNT; i++) {
            if (!s->picture[i].reference)
                ff_mpeg_unref_picture(s, &s->picture[i]);
        }
    }
    s->avctx->coded_frame = &s->current_picture_ptr->f;
}
['static void frame_end(MpegEncContext *s)\n{\n    int i;\n    if (s->unrestricted_mv &&\n        s->current_picture.reference &&\n        !s->intra_only) {\n        const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(s->avctx->pix_fmt);\n        int hshift = desc->log2_chroma_w;\n        int vshift = desc->log2_chroma_h;\n        s->dsp.draw_edges(s->current_picture.f.data[0], s->linesize,\n                          s->h_edge_pos, s->v_edge_pos,\n                          EDGE_WIDTH, EDGE_WIDTH,\n                          EDGE_TOP | EDGE_BOTTOM);\n        s->dsp.draw_edges(s->current_picture.f.data[1], s->uvlinesize,\n                          s->h_edge_pos >> hshift, s->v_edge_pos >> vshift,\n                          EDGE_WIDTH >> hshift, EDGE_WIDTH >> vshift,\n                          EDGE_TOP | EDGE_BOTTOM);\n        s->dsp.draw_edges(s->current_picture.f.data[2], s->uvlinesize,\n                          s->h_edge_pos >> hshift, s->v_edge_pos >> vshift,\n                          EDGE_WIDTH >> hshift, EDGE_WIDTH >> vshift,\n                          EDGE_TOP | EDGE_BOTTOM);\n    }\n    emms_c();\n    s->last_pict_type                 = s->pict_type;\n    s->last_lambda_for [s->pict_type] = s->current_picture_ptr->f.quality;\n    if (s->pict_type!= AV_PICTURE_TYPE_B)\n        s->last_non_b_pict_type = s->pict_type;\n    if (s->encoding) {\n        for (i = 0; i < MAX_PICTURE_COUNT; i++) {\n            if (!s->picture[i].reference)\n                ff_mpeg_unref_picture(s, &s->picture[i]);\n        }\n    }\n    s->avctx->coded_frame = &s->current_picture_ptr->f;\n}', 'const AVPixFmtDescriptor *av_pix_fmt_desc_get(enum AVPixelFormat pix_fmt)\n{\n    if (pix_fmt < 0 || pix_fmt >= AV_PIX_FMT_NB)\n        return NULL;\n    return &av_pix_fmt_descriptors[pix_fmt];\n}']