ffmpeg.c:3699: error: Null Dereference
  pointer `p` last assigned on line 3699 could be null and is dereferenced at line 3699, column 5.

ffmpeg.c:3684:1: start of procedure opt_streamid()
3682. 
3683. /* arg format is "output-stream-index:streamid-value". */
3684. static int opt_streamid(const char *opt, const char *arg)
      ^
3685. {
3686.     int idx;

ffmpeg.c:3690:5: 
3688.     char idx_str[16];
3689. 
3690.     strncpy(idx_str, arg, sizeof(idx_str));
          ^
3691.     idx_str[sizeof(idx_str)-1] = '\0';
3692.     p = strchr(idx_str, ':');

ffmpeg.c:3691:5: 
3689. 
3690.     strncpy(idx_str, arg, sizeof(idx_str));
3691.     idx_str[sizeof(idx_str)-1] = '\0';
          ^
3692.     p = strchr(idx_str, ':');
3693.     if (!p) {

ffmpeg.c:3692:5: 
3690.     strncpy(idx_str, arg, sizeof(idx_str));
3691.     idx_str[sizeof(idx_str)-1] = '\0';
3692.     p = strchr(idx_str, ':');
          ^
3693.     if (!p) {
3694.         fprintf(stderr,

ffmpeg.c:3693:10: Taking true branch
3691.     idx_str[sizeof(idx_str)-1] = '\0';
3692.     p = strchr(idx_str, ':');
3693.     if (!p) {
               ^
3694.         fprintf(stderr,
3695.                 "Invalid value '%s' for option '%s', required syntax is 'index:value'\n",

ffmpeg.c:3694:9: 
3692.     p = strchr(idx_str, ':');
3693.     if (!p) {
3694.         fprintf(stderr,
              ^
3695.                 "Invalid value '%s' for option '%s', required syntax is 'index:value'\n",
3696.                 arg, opt);

ffmpeg.c:3697:9: Skipping ffmpeg_exit(): empty list of specs
3695.                 "Invalid value '%s' for option '%s', required syntax is 'index:value'\n",
3696.                 arg, opt);
3697.         ffmpeg_exit(1);
              ^
3698.     }
3699.     *p++ = '\0';

ffmpeg.c:3699:5: 
3697.         ffmpeg_exit(1);
3698.     }
3699.     *p++ = '\0';
          ^
3700.     idx = parse_number_or_die(opt, idx_str, OPT_INT, 0, MAX_STREAMS-1);
3701.     streamid_map = grow_array(streamid_map, sizeof(*streamid_map), &nb_streamid_map, idx+1);

static int opt_streamid(const char *opt, const char *arg)
{
    int idx;
    char *p;
    char idx_str[16];
    strncpy(idx_str, arg, sizeof(idx_str));
    idx_str[sizeof(idx_str)-1] = '\0';
    p = strchr(idx_str, ':');
    if (!p) {
        fprintf(stderr,
                "Invalid value '%s' for option '%s', required syntax is 'index:value'\n",
                arg, opt);
        ffmpeg_exit(1);
    }
    *p++ = '\0';
    idx = parse_number_or_die(opt, idx_str, OPT_INT, 0, MAX_STREAMS-1);
    streamid_map = grow_array(streamid_map, sizeof(*streamid_map), &nb_streamid_map, idx+1);
    streamid_map[idx] = parse_number_or_die(opt, p, OPT_INT, 0, INT_MAX);
    return 0;
}
['static int opt_streamid(const char *opt, const char *arg)\n{\n    int idx;\n    char *p;\n    char idx_str[16];\n    strncpy(idx_str, arg, sizeof(idx_str));\n    idx_str[sizeof(idx_str)-1] = \'\\0\';\n    p = strchr(idx_str, \':\');\n    if (!p) {\n        fprintf(stderr,\n                "Invalid value \'%s\' for option \'%s\', required syntax is \'index:value\'\\n",\n                arg, opt);\n        ffmpeg_exit(1);\n    }\n    *p++ = \'\\0\';\n    idx = parse_number_or_die(opt, idx_str, OPT_INT, 0, MAX_STREAMS-1);\n    streamid_map = grow_array(streamid_map, sizeof(*streamid_map), &nb_streamid_map, idx+1);\n    streamid_map[idx] = parse_number_or_die(opt, p, OPT_INT, 0, INT_MAX);\n    return 0;\n}']