avconv.c:2551: error: Null Dereference
  pointer `mid` last assigned on line 2551 could be null and is dereferenced at line 2551, column 5.

avconv.c:2543:1: start of procedure opt_metadata()
2541. }
2542. 
2543. static int opt_metadata(const char *opt, const char *arg)
      ^
2544. {
2545.     char *mid= strchr(arg, '=');

avconv.c:2545:5: 
2543. static int opt_metadata(const char *opt, const char *arg)
2544. {
2545.     char *mid= strchr(arg, '=');
          ^
2546. 
2547.     if(!mid){

avconv.c:2547:9: Taking true branch
2545.     char *mid= strchr(arg, '=');
2546. 
2547.     if(!mid){
              ^
2548.         fprintf(stderr, "Missing =\n");
2549.         exit_program(1);

avconv.c:2548:9: 
2546. 
2547.     if(!mid){
2548.         fprintf(stderr, "Missing =\n");
              ^
2549.         exit_program(1);
2550.     }

avconv.c:2549:9: Skipping exit_program(): empty list of specs
2547.     if(!mid){
2548.         fprintf(stderr, "Missing =\n");
2549.         exit_program(1);
              ^
2550.     }
2551.     *mid++= 0;

avconv.c:2551:5: 
2549.         exit_program(1);
2550.     }
2551.     *mid++= 0;
          ^
2552. 
2553.     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}']