libavformat/movenc.c:1841: error: Integer Overflow L2
  ([0, +oo] - 1):unsigned32.

libavformat/movenc.c:1836:1: <LHS trace>
1834. }
1835. 
1836. static int utf8len(const uint8_t *b)
      ^
1837. {
1838.     int len = 0;

libavformat/movenc.c:1836:1: Parameter `*b`
1834. }
1835. 
1836. static int utf8len(const uint8_t *b)
      ^
1837. {
1838.     int len = 0;

libavformat/movenc.c:1841:9: Assignment
1839.     int val;
1840.     while (*b) {
1841.         GET_UTF8(val, *b++, return -1;)
              ^
1842.         len++;
1843.     }

libavformat/movenc.c:1841:9: Assignment
1839.     int val;
1840.     while (*b) {
1841.         GET_UTF8(val, *b++, return -1;)
              ^
1842.         len++;
1843.     }

libavformat/movenc.c:1841:9: Binary operation: ([0, +oo] - 1):unsigned32
1839.     int val;
1840.     while (*b) {
1841.         GET_UTF8(val, *b++, return -1;)
              ^
1842.         len++;
1843.     }
