avconv.c:1494: error: Null Dereference
  pointer `desc` last assigned on line 1491 could be null and is dereferenced at line 1494, column 15.

avconv.c:1484:1: start of procedure get_format()
1482. }
1483. 
1484. static enum AVPixelFormat get_format(AVCodecContext *s, const enum AVPixelFormat *pix_fmts)
      ^
1485. {
1486.     InputStream *ist = s->opaque;

avconv.c:1486:5: 
1484. static enum AVPixelFormat get_format(AVCodecContext *s, const enum AVPixelFormat *pix_fmts)
1485. {
1486.     InputStream *ist = s->opaque;
          ^
1487.     const enum AVPixelFormat *p;
1488.     int ret;

avconv.c:1490:10: 
1488.     int ret;
1489. 
1490.     for (p = pix_fmts; *p != -1; p++) {
               ^
1491.         const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(*p);
1492.         const HWAccel *hwaccel;

avconv.c:1490:24: Loop condition is true. Entering loop body
1488.     int ret;
1489. 
1490.     for (p = pix_fmts; *p != -1; p++) {
                             ^
1491.         const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(*p);
1492.         const HWAccel *hwaccel;

avconv.c:1491:9: 
1489. 
1490.     for (p = pix_fmts; *p != -1; p++) {
1491.         const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(*p);
              ^
1492.         const HWAccel *hwaccel;
1493. 

libavutil/pixdesc.c:1559:1: start of procedure av_pix_fmt_desc_get()
  1557. }
  1558. 
  1559. const AVPixFmtDescriptor *av_pix_fmt_desc_get(enum AVPixelFormat pix_fmt)
        ^
  1560. {
  1561.     if (pix_fmt < 0 || pix_fmt >= AV_PIX_FMT_NB)

libavutil/pixdesc.c:1561:9: Taking false branch
  1559. const AVPixFmtDescriptor *av_pix_fmt_desc_get(enum AVPixelFormat pix_fmt)
  1560. {
  1561.     if (pix_fmt < 0 || pix_fmt >= AV_PIX_FMT_NB)
                ^
  1562.         return NULL;
  1563.     return &av_pix_fmt_descriptors[pix_fmt];

libavutil/pixdesc.c:1561:24: Taking true branch
  1559. const AVPixFmtDescriptor *av_pix_fmt_desc_get(enum AVPixelFormat pix_fmt)
  1560. {
  1561.     if (pix_fmt < 0 || pix_fmt >= AV_PIX_FMT_NB)
                               ^
  1562.         return NULL;
  1563.     return &av_pix_fmt_descriptors[pix_fmt];

libavutil/pixdesc.c:1562:9: 
  1560. {
  1561.     if (pix_fmt < 0 || pix_fmt >= AV_PIX_FMT_NB)
  1562.         return NULL;
                ^
  1563.     return &av_pix_fmt_descriptors[pix_fmt];
  1564. }

libavutil/pixdesc.c:1564:1: return from a call to av_pix_fmt_desc_get
  1562.         return NULL;
  1563.     return &av_pix_fmt_descriptors[pix_fmt];
  1564. }
        ^
  1565. 
  1566. const AVPixFmtDescriptor *av_pix_fmt_desc_next(const AVPixFmtDescriptor *prev)

avconv.c:1494:15: 
1492.         const HWAccel *hwaccel;
1493. 
1494.         if (!(desc->flags & AV_PIX_FMT_FLAG_HWACCEL))
                    ^
1495.             break;
1496. 
