ffmpeg.c:2792: error: Null Dereference
  pointer `mid` last assigned on line 2792 could be null and is dereferenced at line 2792, column 5.

ffmpeg.c:2784:1: start of procedure opt_metadata()
2782. }
2783. 
2784. static int opt_metadata(const char *opt, const char *arg)
      ^
2785. {
2786.     char *mid= strchr(arg, '=');

ffmpeg.c:2786:5: 
2784. static int opt_metadata(const char *opt, const char *arg)
2785. {
2786.     char *mid= strchr(arg, '=');
          ^
2787. 
2788.     if(!mid){

ffmpeg.c:2788:9: Taking true branch
2786.     char *mid= strchr(arg, '=');
2787. 
2788.     if(!mid){
              ^
2789.         fprintf(stderr, "Missing =\n");
2790.         ffmpeg_exit(1);

ffmpeg.c:2789:9: 
2787. 
2788.     if(!mid){
2789.         fprintf(stderr, "Missing =\n");
              ^
2790.         ffmpeg_exit(1);
2791.     }

ffmpeg.c:2790:9: Skipping ffmpeg_exit(): empty list of specs
2788.     if(!mid){
2789.         fprintf(stderr, "Missing =\n");
2790.         ffmpeg_exit(1);
              ^
2791.     }
2792.     *mid++= 0;

ffmpeg.c:2792:5: 
2790.         ffmpeg_exit(1);
2791.     }
2792.     *mid++= 0;
          ^
2793. 
2794.     av_metadata_set2(&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_metadata_set2(&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_metadata_set2(&metadata, arg, mid, 0);\n    return 0;\n}']