ffmpeg.c:3644: error: Null Dereference
  pointer `p` last assigned on line 3644 could be null and is dereferenced at line 3644, column 5.

ffmpeg.c:3629:1: start of procedure opt_streamid()
3627. 
3628. /* arg format is "output-stream-index:streamid-value". */
3629. static int opt_streamid(const char *opt, const char *arg)
      ^
3630. {
3631.     int idx;

ffmpeg.c:3635:5: 
3633.     char idx_str[16];
3634. 
3635.     strncpy(idx_str, arg, sizeof(idx_str));
          ^
3636.     idx_str[sizeof(idx_str)-1] = '\0';
3637.     p = strchr(idx_str, ':');

ffmpeg.c:3636:5: 
3634. 
3635.     strncpy(idx_str, arg, sizeof(idx_str));
3636.     idx_str[sizeof(idx_str)-1] = '\0';
          ^
3637.     p = strchr(idx_str, ':');
3638.     if (!p) {

ffmpeg.c:3637:5: 
3635.     strncpy(idx_str, arg, sizeof(idx_str));
3636.     idx_str[sizeof(idx_str)-1] = '\0';
3637.     p = strchr(idx_str, ':');
          ^
3638.     if (!p) {
3639.         fprintf(stderr,

ffmpeg.c:3638:10: Taking true branch
3636.     idx_str[sizeof(idx_str)-1] = '\0';
3637.     p = strchr(idx_str, ':');
3638.     if (!p) {
               ^
3639.         fprintf(stderr,
3640.                 "Invalid value '%s' for option '%s', required syntax is 'index:value'\n",

ffmpeg.c:3639:9: 
3637.     p = strchr(idx_str, ':');
3638.     if (!p) {
3639.         fprintf(stderr,
              ^
3640.                 "Invalid value '%s' for option '%s', required syntax is 'index:value'\n",
3641.                 arg, opt);

ffmpeg.c:3642:9: Skipping ffmpeg_exit(): empty list of specs
3640.                 "Invalid value '%s' for option '%s', required syntax is 'index:value'\n",
3641.                 arg, opt);
3642.         ffmpeg_exit(1);
              ^
3643.     }
3644.     *p++ = '\0';

ffmpeg.c:3644:5: 
3642.         ffmpeg_exit(1);
3643.     }
3644.     *p++ = '\0';
          ^
3645.     idx = parse_number_or_die(opt, idx_str, OPT_INT, 0, MAX_STREAMS-1);
3646.     streamid_map = grow_array(streamid_map, sizeof(*streamid_map), &nb_streamid_map, idx+1);
