avconv.c:1473: error: Null Dereference
  pointer `desc` last assigned on line 1470 could be null and is dereferenced at line 1473, column 15.

avconv.c:1463:1: start of procedure get_format()
1461. }
1462. 
1463. static enum AVPixelFormat get_format(AVCodecContext *s, const enum AVPixelFormat *pix_fmts)
      ^
1464. {
1465.     InputStream *ist = s->opaque;

avconv.c:1465:5: 
1463. static enum AVPixelFormat get_format(AVCodecContext *s, const enum AVPixelFormat *pix_fmts)
1464. {
1465.     InputStream *ist = s->opaque;
          ^
1466.     const enum AVPixelFormat *p;
1467.     int ret;

avconv.c:1469:10: 
1467.     int ret;
1468. 
1469.     for (p = pix_fmts; *p != -1; p++) {
               ^
1470.         const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(*p);
1471.         const HWAccel *hwaccel;

avconv.c:1469:24: Loop condition is true. Entering loop body
1467.     int ret;
1468. 
1469.     for (p = pix_fmts; *p != -1; p++) {
                             ^
1470.         const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(*p);
1471.         const HWAccel *hwaccel;

avconv.c:1470:9: 
1468. 
1469.     for (p = pix_fmts; *p != -1; p++) {
1470.         const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(*p);
              ^
1471.         const HWAccel *hwaccel;
1472. 

libavutil/pixdesc.c:1703:1: start of procedure av_pix_fmt_desc_get()
  1701. }
  1702. 
  1703. const AVPixFmtDescriptor *av_pix_fmt_desc_get(enum AVPixelFormat pix_fmt)
        ^
  1704. {
  1705.     if (pix_fmt < 0 || pix_fmt >= AV_PIX_FMT_NB)

libavutil/pixdesc.c:1705:9: Taking false branch
  1703. const AVPixFmtDescriptor *av_pix_fmt_desc_get(enum AVPixelFormat pix_fmt)
  1704. {
  1705.     if (pix_fmt < 0 || pix_fmt >= AV_PIX_FMT_NB)
                ^
  1706.         return NULL;
  1707.     return &av_pix_fmt_descriptors[pix_fmt];

libavutil/pixdesc.c:1705:24: Taking true branch
  1703. const AVPixFmtDescriptor *av_pix_fmt_desc_get(enum AVPixelFormat pix_fmt)
  1704. {
  1705.     if (pix_fmt < 0 || pix_fmt >= AV_PIX_FMT_NB)
                               ^
  1706.         return NULL;
  1707.     return &av_pix_fmt_descriptors[pix_fmt];

libavutil/pixdesc.c:1706:9: 
  1704. {
  1705.     if (pix_fmt < 0 || pix_fmt >= AV_PIX_FMT_NB)
  1706.         return NULL;
                ^
  1707.     return &av_pix_fmt_descriptors[pix_fmt];
  1708. }

libavutil/pixdesc.c:1708:1: return from a call to av_pix_fmt_desc_get
  1706.         return NULL;
  1707.     return &av_pix_fmt_descriptors[pix_fmt];
  1708. }
        ^
  1709. 
  1710. const AVPixFmtDescriptor *av_pix_fmt_desc_next(const AVPixFmtDescriptor *prev)

avconv.c:1473:15: 
1471.         const HWAccel *hwaccel;
1472. 
1473.         if (!(desc->flags & AV_PIX_FMT_FLAG_HWACCEL))
                    ^
1474.             break;
1475. 
