static int opt_vstats(void *optctx, const char *opt, const char *arg)
{
    char filename[40];
    time_t today2 = time(NULL);
    struct tm *today = localtime(&today2);

    if (!today)
        return AVERROR(errno);

    snprintf(filename, sizeof(filename), "vstats_%02d%02d%02d.log", today->tm_hour, today->tm_min,
             today->tm_sec);
    return opt_vstats_file(NULL, opt, filename);
}