avconv.c:2549: error: Null Dereference
  pointer `mid` last assigned on line 2549 could be null and is dereferenced at line 2549, column 5.

avconv.c:2541:1: start of procedure opt_metadata()
2539. }
2540. 
2541. static int opt_metadata(const char *opt, const char *arg)
      ^
2542. {
2543.     char *mid= strchr(arg, '=');

avconv.c:2543:5: 
2541. static int opt_metadata(const char *opt, const char *arg)
2542. {
2543.     char *mid= strchr(arg, '=');
          ^
2544. 
2545.     if(!mid){

avconv.c:2545:9: Taking true branch
2543.     char *mid= strchr(arg, '=');
2544. 
2545.     if(!mid){
              ^
2546.         fprintf(stderr, "Missing =\n");
2547.         exit_program(1);

avconv.c:2546:9: 
2544. 
2545.     if(!mid){
2546.         fprintf(stderr, "Missing =\n");
              ^
2547.         exit_program(1);
2548.     }

avconv.c:2547:9: Skipping exit_program(): empty list of specs
2545.     if(!mid){
2546.         fprintf(stderr, "Missing =\n");
2547.         exit_program(1);
              ^
2548.     }
2549.     *mid++= 0;

avconv.c:2549:5: 
2547.         exit_program(1);
2548.     }
2549.     *mid++= 0;
          ^
2550. 
2551.     av_dict_set(&metadata, arg, mid, 0);
