libswscale/swscale_unscaled.c:1118: error: Null Dereference
  pointer `desc` last assigned on line 1114 could be null and is dereferenced at line 1118, column 21.

libswscale/swscale_unscaled.c:1111:1: start of procedure check_image_pointers()
1109. }
1110. 
1111. static int check_image_pointers(uint8_t *data[4], enum AVPixelFormat pix_fmt,
      ^
1112.                                 const int linesizes[4])
1113. {

libswscale/swscale_unscaled.c:1114:5: 
1112.                                 const int linesizes[4])
1113. {
1114.     const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(pix_fmt);
          ^
1115.     int i;
1116. 

libavutil/pixdesc.c:1464:1: start of procedure av_pix_fmt_desc_get()
  1462. }
  1463. 
  1464. const AVPixFmtDescriptor *av_pix_fmt_desc_get(enum AVPixelFormat pix_fmt)
        ^
  1465. {
  1466.     if (pix_fmt < 0 || pix_fmt >= AV_PIX_FMT_NB)

libavutil/pixdesc.c:1466:9: Taking false branch
  1464. const AVPixFmtDescriptor *av_pix_fmt_desc_get(enum AVPixelFormat pix_fmt)
  1465. {
  1466.     if (pix_fmt < 0 || pix_fmt >= AV_PIX_FMT_NB)
                ^
  1467.         return NULL;
  1468.     return &av_pix_fmt_descriptors[pix_fmt];

libavutil/pixdesc.c:1466:24: Taking true branch
  1464. const AVPixFmtDescriptor *av_pix_fmt_desc_get(enum AVPixelFormat pix_fmt)
  1465. {
  1466.     if (pix_fmt < 0 || pix_fmt >= AV_PIX_FMT_NB)
                               ^
  1467.         return NULL;
  1468.     return &av_pix_fmt_descriptors[pix_fmt];

libavutil/pixdesc.c:1467:9: 
  1465. {
  1466.     if (pix_fmt < 0 || pix_fmt >= AV_PIX_FMT_NB)
  1467.         return NULL;
                ^
  1468.     return &av_pix_fmt_descriptors[pix_fmt];
  1469. }

libavutil/pixdesc.c:1469:1: return from a call to av_pix_fmt_desc_get
  1467.         return NULL;
  1468.     return &av_pix_fmt_descriptors[pix_fmt];
  1469. }
        ^
  1470. 
  1471. const AVPixFmtDescriptor *av_pix_fmt_desc_next(const AVPixFmtDescriptor *prev)

libswscale/swscale_unscaled.c:1117:10: 
1115.     int i;
1116. 
1117.     for (i = 0; i < 4; i++) {
               ^
1118.         int plane = desc->comp[i].plane;
1119.         if (!data[plane] || !linesizes[plane])

libswscale/swscale_unscaled.c:1117:17: Loop condition is true. Entering loop body
1115.     int i;
1116. 
1117.     for (i = 0; i < 4; i++) {
                      ^
1118.         int plane = desc->comp[i].plane;
1119.         if (!data[plane] || !linesizes[plane])

libswscale/swscale_unscaled.c:1118:9: 
1116. 
1117.     for (i = 0; i < 4; i++) {
1118.         int plane = desc->comp[i].plane;
              ^
1119.         if (!data[plane] || !linesizes[plane])
1120.             return 0;
