libavformat/rtsp.c:957: error: Integer Overflow R2
  ([0, +oo] + [0, +oo]):signed32 by call to `av_strlcatf`.

libavformat/rtsp.c:947:5: Call
945.     av_strlcpy(buf, cmd, sizeof(buf));
946.     snprintf(buf1, sizeof(buf1), "CSeq: %d\r\n", rt->seq);
947.     av_strlcat(buf, buf1, sizeof(buf));
         ^
948.     if (rt->session_id[0] != '\0' && !strstr(cmd, "\nIf-Match:")) {
949.         snprintf(buf1, sizeof(buf1), "Session: %s\r\n", rt->session_id);

libavutil/avstring.c:61:1: Parameter `dst->strlen`
  59. }
  60. 
  61. size_t av_strlcat(char *dst, const char *src, size_t size)
      ^
  62. {
  63.     size_t len = strlen(dst);

libavformat/rtsp.c:957:9: Call
955.                     rt->auth_b64);
956.     if (send_content_length > 0 && send_content)
957.         av_strlcatf(buf, sizeof(buf), "Content-Length: %d\r\n", send_content_length);
             ^
958.     av_strlcat(buf, "\r\n", sizeof(buf));
959. 

libavutil/avstring.c:69:1: <LHS trace>
67. }
68. 
69. size_t av_strlcatf(char *dst, size_t size, const char *fmt, ...)
    ^
70. {
71.     int len = strlen(dst);

libavutil/avstring.c:69:1: Parameter `size`
  67. }
  68. 
  69. size_t av_strlcatf(char *dst, size_t size, const char *fmt, ...)
      ^
  70. {
  71.     int len = strlen(dst);

libavutil/avstring.c:75:12: <RHS trace>
73. 
74.     va_start(vl, fmt);
75.     len += vsnprintf(dst + len, size > len ? size - len : 0, fmt, vl);
               ^
76.     va_end(vl);
77. 

libavutil/avstring.c:75:12: Risky value from: vsnprintf
  73. 
  74.     va_start(vl, fmt);
  75.     len += vsnprintf(dst + len, size > len ? size - len : 0, fmt, vl);
                 ^
  76.     va_end(vl);
  77. 

libavutil/avstring.c:75:5: Binary operation: ([0, +oo] + [0, +oo]):signed32 by call to `av_strlcatf` 
  73. 
  74.     va_start(vl, fmt);
  75.     len += vsnprintf(dst + len, size > len ? size - len : 0, fmt, vl);
          ^
  76.     va_end(vl);
  77. 
