avconv.c:1613: error: Null Dereference
  pointer `desc` last assigned on line 1610 could be null and is dereferenced at line 1613, column 15.

avconv.c:1603:1: start of procedure get_format()
1601. }
1602. 
1603. static enum AVPixelFormat get_format(AVCodecContext *s, const enum AVPixelFormat *pix_fmts)
      ^
1604. {
1605.     InputStream *ist = s->opaque;

avconv.c:1605:5: 
1603. static enum AVPixelFormat get_format(AVCodecContext *s, const enum AVPixelFormat *pix_fmts)
1604. {
1605.     InputStream *ist = s->opaque;
          ^
1606.     const enum AVPixelFormat *p;
1607.     int ret;

avconv.c:1609:10: 
1607.     int ret;
1608. 
1609.     for (p = pix_fmts; *p != -1; p++) {
               ^
1610.         const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(*p);
1611.         const HWAccel *hwaccel;

avconv.c:1609:24: Loop condition is true. Entering loop body
1607.     int ret;
1608. 
1609.     for (p = pix_fmts; *p != -1; p++) {
                             ^
1610.         const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(*p);
1611.         const HWAccel *hwaccel;

avconv.c:1610:9: 
1608. 
1609.     for (p = pix_fmts; *p != -1; p++) {
1610.         const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(*p);
              ^
1611.         const HWAccel *hwaccel;
1612. 

libavutil/pixdesc.c:1768:1: start of procedure av_pix_fmt_desc_get()
  1766. }
  1767. 
  1768. const AVPixFmtDescriptor *av_pix_fmt_desc_get(enum AVPixelFormat pix_fmt)
        ^
  1769. {
  1770.     if (pix_fmt < 0 || pix_fmt >= AV_PIX_FMT_NB)

libavutil/pixdesc.c:1770:9: Taking false branch
  1768. const AVPixFmtDescriptor *av_pix_fmt_desc_get(enum AVPixelFormat pix_fmt)
  1769. {
  1770.     if (pix_fmt < 0 || pix_fmt >= AV_PIX_FMT_NB)
                ^
  1771.         return NULL;
  1772.     return &av_pix_fmt_descriptors[pix_fmt];

libavutil/pixdesc.c:1770:24: Taking true branch
  1768. const AVPixFmtDescriptor *av_pix_fmt_desc_get(enum AVPixelFormat pix_fmt)
  1769. {
  1770.     if (pix_fmt < 0 || pix_fmt >= AV_PIX_FMT_NB)
                               ^
  1771.         return NULL;
  1772.     return &av_pix_fmt_descriptors[pix_fmt];

libavutil/pixdesc.c:1771:9: 
  1769. {
  1770.     if (pix_fmt < 0 || pix_fmt >= AV_PIX_FMT_NB)
  1771.         return NULL;
                ^
  1772.     return &av_pix_fmt_descriptors[pix_fmt];
  1773. }

libavutil/pixdesc.c:1773:1: return from a call to av_pix_fmt_desc_get
  1771.         return NULL;
  1772.     return &av_pix_fmt_descriptors[pix_fmt];
  1773. }
        ^
  1774. 
  1775. const AVPixFmtDescriptor *av_pix_fmt_desc_next(const AVPixFmtDescriptor *prev)

avconv.c:1613:15: 
1611.         const HWAccel *hwaccel;
1612. 
1613.         if (!(desc->flags & AV_PIX_FMT_FLAG_HWACCEL))
                    ^
1614.             break;
1615. 
