avconv.c:1465: error: Null Dereference
  pointer `desc` last assigned on line 1462 could be null and is dereferenced at line 1465, column 15.

avconv.c:1455:1: start of procedure get_format()
1453. }
1454. 
1455. static enum AVPixelFormat get_format(AVCodecContext *s, const enum AVPixelFormat *pix_fmts)
      ^
1456. {
1457.     InputStream *ist = s->opaque;

avconv.c:1457:5: 
1455. static enum AVPixelFormat get_format(AVCodecContext *s, const enum AVPixelFormat *pix_fmts)
1456. {
1457.     InputStream *ist = s->opaque;
          ^
1458.     const enum AVPixelFormat *p;
1459.     int ret;

avconv.c:1461:10: 
1459.     int ret;
1460. 
1461.     for (p = pix_fmts; *p != -1; p++) {
               ^
1462.         const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(*p);
1463.         const HWAccel *hwaccel;

avconv.c:1461:24: Loop condition is true. Entering loop body
1459.     int ret;
1460. 
1461.     for (p = pix_fmts; *p != -1; p++) {
                             ^
1462.         const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(*p);
1463.         const HWAccel *hwaccel;

avconv.c:1462:9: 
1460. 
1461.     for (p = pix_fmts; *p != -1; p++) {
1462.         const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(*p);
              ^
1463.         const HWAccel *hwaccel;
1464. 

libavutil/pixdesc.c:1689:1: start of procedure av_pix_fmt_desc_get()
  1687. }
  1688. 
  1689. const AVPixFmtDescriptor *av_pix_fmt_desc_get(enum AVPixelFormat pix_fmt)
        ^
  1690. {
  1691.     if (pix_fmt < 0 || pix_fmt >= AV_PIX_FMT_NB)

libavutil/pixdesc.c:1691:9: Taking false branch
  1689. const AVPixFmtDescriptor *av_pix_fmt_desc_get(enum AVPixelFormat pix_fmt)
  1690. {
  1691.     if (pix_fmt < 0 || pix_fmt >= AV_PIX_FMT_NB)
                ^
  1692.         return NULL;
  1693.     return &av_pix_fmt_descriptors[pix_fmt];

libavutil/pixdesc.c:1691:24: Taking true branch
  1689. const AVPixFmtDescriptor *av_pix_fmt_desc_get(enum AVPixelFormat pix_fmt)
  1690. {
  1691.     if (pix_fmt < 0 || pix_fmt >= AV_PIX_FMT_NB)
                               ^
  1692.         return NULL;
  1693.     return &av_pix_fmt_descriptors[pix_fmt];

libavutil/pixdesc.c:1692:9: 
  1690. {
  1691.     if (pix_fmt < 0 || pix_fmt >= AV_PIX_FMT_NB)
  1692.         return NULL;
                ^
  1693.     return &av_pix_fmt_descriptors[pix_fmt];
  1694. }

libavutil/pixdesc.c:1694:1: return from a call to av_pix_fmt_desc_get
  1692.         return NULL;
  1693.     return &av_pix_fmt_descriptors[pix_fmt];
  1694. }
        ^
  1695. 
  1696. const AVPixFmtDescriptor *av_pix_fmt_desc_next(const AVPixFmtDescriptor *prev)

avconv.c:1465:15: 
1463.         const HWAccel *hwaccel;
1464. 
1465.         if (!(desc->flags & AV_PIX_FMT_FLAG_HWACCEL))
                    ^
1466.             break;
1467. 
