set_opt(encoder, "nonref_p", "1");
set_opt(encoder, "preset", "llhp");
set_opt(encoder, "rc", "cbr_ld_hq");
set_opt(encoder, "zerolatency", "1");
set_opt(encoder, "delay", "0");

void set_opt(encoder_t *encoder, char* option, char* value) {
  int ret = av_opt_set(encoder->context->priv_data, option, value, 0);
  if (ret < 0) {
    mprintf("Could not av_opt_set %s to %s!", option, value);
  }
}