ffmpeg.c:3678: error: Null Dereference
  pointer `p` last assigned on line 3678 could be null and is dereferenced at line 3678, column 5.

ffmpeg.c:3663:1: start of procedure opt_streamid()
3661. 
3662. /* arg format is "output-stream-index:streamid-value". */
3663. static int opt_streamid(const char *opt, const char *arg)
      ^
3664. {
3665.     int idx;

ffmpeg.c:3669:5: 
3667.     char idx_str[16];
3668. 
3669.     strncpy(idx_str, arg, sizeof(idx_str));
          ^
3670.     idx_str[sizeof(idx_str)-1] = '\0';
3671.     p = strchr(idx_str, ':');

ffmpeg.c:3670:5: 
3668. 
3669.     strncpy(idx_str, arg, sizeof(idx_str));
3670.     idx_str[sizeof(idx_str)-1] = '\0';
          ^
3671.     p = strchr(idx_str, ':');
3672.     if (!p) {

ffmpeg.c:3671:5: 
3669.     strncpy(idx_str, arg, sizeof(idx_str));
3670.     idx_str[sizeof(idx_str)-1] = '\0';
3671.     p = strchr(idx_str, ':');
          ^
3672.     if (!p) {
3673.         fprintf(stderr,

ffmpeg.c:3672:10: Taking true branch
3670.     idx_str[sizeof(idx_str)-1] = '\0';
3671.     p = strchr(idx_str, ':');
3672.     if (!p) {
               ^
3673.         fprintf(stderr,
3674.                 "Invalid value '%s' for option '%s', required syntax is 'index:value'\n",

ffmpeg.c:3673:9: 
3671.     p = strchr(idx_str, ':');
3672.     if (!p) {
3673.         fprintf(stderr,
              ^
3674.                 "Invalid value '%s' for option '%s', required syntax is 'index:value'\n",
3675.                 arg, opt);

ffmpeg.c:3676:9: Skipping ffmpeg_exit(): empty list of specs
3674.                 "Invalid value '%s' for option '%s', required syntax is 'index:value'\n",
3675.                 arg, opt);
3676.         ffmpeg_exit(1);
              ^
3677.     }
3678.     *p++ = '\0';

ffmpeg.c:3678:5: 
3676.         ffmpeg_exit(1);
3677.     }
3678.     *p++ = '\0';
          ^
3679.     idx = parse_number_or_die(opt, idx_str, OPT_INT, 0, MAX_STREAMS-1);
3680.     streamid_map = grow_array(streamid_map, sizeof(*streamid_map), &nb_streamid_map, idx+1);
