avconv.c:2525: error: Null Dereference
  pointer `mid` last assigned on line 2525 could be null and is dereferenced at line 2525, column 5.

avconv.c:2517:1: start of procedure opt_metadata()
2515. }
2516. 
2517. static int opt_metadata(const char *opt, const char *arg)
      ^
2518. {
2519.     char *mid= strchr(arg, '=');

avconv.c:2519:5: 
2517. static int opt_metadata(const char *opt, const char *arg)
2518. {
2519.     char *mid= strchr(arg, '=');
          ^
2520. 
2521.     if(!mid){

avconv.c:2521:9: Taking true branch
2519.     char *mid= strchr(arg, '=');
2520. 
2521.     if(!mid){
              ^
2522.         fprintf(stderr, "Missing =\n");
2523.         exit_program(1);

avconv.c:2522:9: 
2520. 
2521.     if(!mid){
2522.         fprintf(stderr, "Missing =\n");
              ^
2523.         exit_program(1);
2524.     }

avconv.c:2523:9: Skipping exit_program(): empty list of specs
2521.     if(!mid){
2522.         fprintf(stderr, "Missing =\n");
2523.         exit_program(1);
              ^
2524.     }
2525.     *mid++= 0;

avconv.c:2525:5: 
2523.         exit_program(1);
2524.     }
2525.     *mid++= 0;
          ^
2526. 
2527.     av_dict_set(&metadata, arg, mid, 0);
