ffmpeg.c:2864: error: Null Dereference
  pointer `mid` last assigned on line 2864 could be null and is dereferenced at line 2864, column 5.

ffmpeg.c:2856:1: start of procedure opt_metadata()
2854. }
2855. 
2856. static int opt_metadata(const char *opt, const char *arg)
      ^
2857. {
2858.     char *mid= strchr(arg, '=');

ffmpeg.c:2858:5: 
2856. static int opt_metadata(const char *opt, const char *arg)
2857. {
2858.     char *mid= strchr(arg, '=');
          ^
2859. 
2860.     if(!mid){

ffmpeg.c:2860:9: Taking true branch
2858.     char *mid= strchr(arg, '=');
2859. 
2860.     if(!mid){
              ^
2861.         fprintf(stderr, "Missing =\n");
2862.         ffmpeg_exit(1);

ffmpeg.c:2861:9: 
2859. 
2860.     if(!mid){
2861.         fprintf(stderr, "Missing =\n");
              ^
2862.         ffmpeg_exit(1);
2863.     }

ffmpeg.c:2862:9: Skipping ffmpeg_exit(): empty list of specs
2860.     if(!mid){
2861.         fprintf(stderr, "Missing =\n");
2862.         ffmpeg_exit(1);
              ^
2863.     }
2864.     *mid++= 0;

ffmpeg.c:2864:5: 
2862.         ffmpeg_exit(1);
2863.     }
2864.     *mid++= 0;
          ^
2865. 
2866.     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");
        ffmpeg_exit(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        ffmpeg_exit(1);\n    }\n    *mid++= 0;\n    av_dict_set(&metadata, arg, mid, 0);\n    return 0;\n}']