avconv.c:1453: error: Null Dereference
  pointer `desc` last assigned on line 1450 could be null and is dereferenced at line 1453, column 15.

avconv.c:1443:1: start of procedure get_format()
1441. }
1442. 
1443. static enum AVPixelFormat get_format(AVCodecContext *s, const enum AVPixelFormat *pix_fmts)
      ^
1444. {
1445.     InputStream *ist = s->opaque;

avconv.c:1445:5: 
1443. static enum AVPixelFormat get_format(AVCodecContext *s, const enum AVPixelFormat *pix_fmts)
1444. {
1445.     InputStream *ist = s->opaque;
          ^
1446.     const enum AVPixelFormat *p;
1447.     int ret;

avconv.c:1449:10: 
1447.     int ret;
1448. 
1449.     for (p = pix_fmts; *p != -1; p++) {
               ^
1450.         const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(*p);
1451.         const HWAccel *hwaccel;

avconv.c:1449:24: Loop condition is true. Entering loop body
1447.     int ret;
1448. 
1449.     for (p = pix_fmts; *p != -1; p++) {
                             ^
1450.         const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(*p);
1451.         const HWAccel *hwaccel;

avconv.c:1450:9: 
1448. 
1449.     for (p = pix_fmts; *p != -1; p++) {
1450.         const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(*p);
              ^
1451.         const HWAccel *hwaccel;
1452. 

libavutil/pixdesc.c:1682:1: start of procedure av_pix_fmt_desc_get()
  1680. }
  1681. 
  1682. const AVPixFmtDescriptor *av_pix_fmt_desc_get(enum AVPixelFormat pix_fmt)
        ^
  1683. {
  1684.     if (pix_fmt < 0 || pix_fmt >= AV_PIX_FMT_NB)

libavutil/pixdesc.c:1684:9: Taking false branch
  1682. const AVPixFmtDescriptor *av_pix_fmt_desc_get(enum AVPixelFormat pix_fmt)
  1683. {
  1684.     if (pix_fmt < 0 || pix_fmt >= AV_PIX_FMT_NB)
                ^
  1685.         return NULL;
  1686.     return &av_pix_fmt_descriptors[pix_fmt];

libavutil/pixdesc.c:1684:24: Taking true branch
  1682. const AVPixFmtDescriptor *av_pix_fmt_desc_get(enum AVPixelFormat pix_fmt)
  1683. {
  1684.     if (pix_fmt < 0 || pix_fmt >= AV_PIX_FMT_NB)
                               ^
  1685.         return NULL;
  1686.     return &av_pix_fmt_descriptors[pix_fmt];

libavutil/pixdesc.c:1685:9: 
  1683. {
  1684.     if (pix_fmt < 0 || pix_fmt >= AV_PIX_FMT_NB)
  1685.         return NULL;
                ^
  1686.     return &av_pix_fmt_descriptors[pix_fmt];
  1687. }

libavutil/pixdesc.c:1687:1: return from a call to av_pix_fmt_desc_get
  1685.         return NULL;
  1686.     return &av_pix_fmt_descriptors[pix_fmt];
  1687. }
        ^
  1688. 
  1689. const AVPixFmtDescriptor *av_pix_fmt_desc_next(const AVPixFmtDescriptor *prev)

avconv.c:1453:15: 
1451.         const HWAccel *hwaccel;
1452. 
1453.         if (!(desc->flags & AV_PIX_FMT_FLAG_HWACCEL))
                    ^
1454.             break;
1455. 
