avconv.c:2537: error: Null Dereference
  pointer `mid` last assigned on line 2537 could be null and is dereferenced at line 2537, column 5.

avconv.c:2529:1: start of procedure opt_metadata()
2527. }
2528. 
2529. static int opt_metadata(const char *opt, const char *arg)
      ^
2530. {
2531.     char *mid= strchr(arg, '=');

avconv.c:2531:5: 
2529. static int opt_metadata(const char *opt, const char *arg)
2530. {
2531.     char *mid= strchr(arg, '=');
          ^
2532. 
2533.     if(!mid){

avconv.c:2533:9: Taking true branch
2531.     char *mid= strchr(arg, '=');
2532. 
2533.     if(!mid){
              ^
2534.         fprintf(stderr, "Missing =\n");
2535.         exit_program(1);

avconv.c:2534:9: 
2532. 
2533.     if(!mid){
2534.         fprintf(stderr, "Missing =\n");
              ^
2535.         exit_program(1);
2536.     }

avconv.c:2535:9: Skipping exit_program(): empty list of specs
2533.     if(!mid){
2534.         fprintf(stderr, "Missing =\n");
2535.         exit_program(1);
              ^
2536.     }
2537.     *mid++= 0;

avconv.c:2537:5: 
2535.         exit_program(1);
2536.     }
2537.     *mid++= 0;
          ^
2538. 
2539.     av_dict_set(&metadata, arg, mid, 0);

static int opt_metadata(const char *opt, const char *arg)
{
    char *mid= strchr(arg, '=');
    if(!mid){
        fprintf(stderr, "Missing =\n");
        exit_program(1);
    }
    *mid++= 0;
    av_dict_set(&metadata, arg, mid, 0);
    return 0;
}
['static int opt_metadata(const char *opt, const char *arg)\n{\n    char *mid= strchr(arg, \'=\');\n    if(!mid){\n        fprintf(stderr, "Missing =\\n");\n        exit_program(1);\n    }\n    *mid++= 0;\n    av_dict_set(&metadata, arg, mid, 0);\n    return 0;\n}']