avconv.c:1464: error: Null Dereference
  pointer `desc` last assigned on line 1461 could be null and is dereferenced at line 1464, column 15.

avconv.c:1454:1: start of procedure get_format()
1452. }
1453. 
1454. static enum AVPixelFormat get_format(AVCodecContext *s, const enum AVPixelFormat *pix_fmts)
      ^
1455. {
1456.     InputStream *ist = s->opaque;

avconv.c:1456:5: 
1454. static enum AVPixelFormat get_format(AVCodecContext *s, const enum AVPixelFormat *pix_fmts)
1455. {
1456.     InputStream *ist = s->opaque;
          ^
1457.     const enum AVPixelFormat *p;
1458.     int ret;

avconv.c:1460:10: 
1458.     int ret;
1459. 
1460.     for (p = pix_fmts; *p != -1; p++) {
               ^
1461.         const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(*p);
1462.         const HWAccel *hwaccel;

avconv.c:1460:24: Loop condition is true. Entering loop body
1458.     int ret;
1459. 
1460.     for (p = pix_fmts; *p != -1; p++) {
                             ^
1461.         const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(*p);
1462.         const HWAccel *hwaccel;

avconv.c:1461:9: 
1459. 
1460.     for (p = pix_fmts; *p != -1; p++) {
1461.         const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(*p);
              ^
1462.         const HWAccel *hwaccel;
1463. 

libavutil/pixdesc.c:1686:1: start of procedure av_pix_fmt_desc_get()
  1684. }
  1685. 
  1686. const AVPixFmtDescriptor *av_pix_fmt_desc_get(enum AVPixelFormat pix_fmt)
        ^
  1687. {
  1688.     if (pix_fmt < 0 || pix_fmt >= AV_PIX_FMT_NB)

libavutil/pixdesc.c:1688:9: Taking false branch
  1686. const AVPixFmtDescriptor *av_pix_fmt_desc_get(enum AVPixelFormat pix_fmt)
  1687. {
  1688.     if (pix_fmt < 0 || pix_fmt >= AV_PIX_FMT_NB)
                ^
  1689.         return NULL;
  1690.     return &av_pix_fmt_descriptors[pix_fmt];

libavutil/pixdesc.c:1688:24: Taking true branch
  1686. const AVPixFmtDescriptor *av_pix_fmt_desc_get(enum AVPixelFormat pix_fmt)
  1687. {
  1688.     if (pix_fmt < 0 || pix_fmt >= AV_PIX_FMT_NB)
                               ^
  1689.         return NULL;
  1690.     return &av_pix_fmt_descriptors[pix_fmt];

libavutil/pixdesc.c:1689:9: 
  1687. {
  1688.     if (pix_fmt < 0 || pix_fmt >= AV_PIX_FMT_NB)
  1689.         return NULL;
                ^
  1690.     return &av_pix_fmt_descriptors[pix_fmt];
  1691. }

libavutil/pixdesc.c:1691:1: return from a call to av_pix_fmt_desc_get
  1689.         return NULL;
  1690.     return &av_pix_fmt_descriptors[pix_fmt];
  1691. }
        ^
  1692. 
  1693. const AVPixFmtDescriptor *av_pix_fmt_desc_next(const AVPixFmtDescriptor *prev)

avconv.c:1464:15: 
1462.         const HWAccel *hwaccel;
1463. 
1464.         if (!(desc->flags & AV_PIX_FMT_FLAG_HWACCEL))
                    ^
1465.             break;
1466. 
